How to Introduce a New Pet to a Resident Pet Without Fights

A guide to Prepare the house before the animals can see each other, Trade scent for several days before any sight, Read the body language at the barrier, Run the first contact by species pair, Settle in and check on welfare for weeks

Co-authored by Howcompass Pets Desk✓ and Howcompass Editorial Team

Last Updated: November 4, 2026 Fact Checked

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The worst introductions happen on day one, in the middle of the living room, with everyone excited and no exit, and the recovery takes months rather than days. Animals do not need to meet on the day they share a house; they need to learn that the other one predicts good things and never predicts a chase, and that takes a week or two of closed doors, swapped bedding and short, deliberately boring sessions. This guide walks that sequence for the pairs people actually bring home, cat with cat, dog with cat, dog with dog, and the prey-animal combinations where a single unsupervised second can be fatal. It also gives you the welfare red lines: no punishment for growling, no restraining a cat in front of a dog, and a same-day veterinary call for bite wounds, blocked urination or a cat that has not eaten for two days. Whether you are starting with Prepare the house before the animals can see each other or moving on to Trade scent for several days before any sight, Read the body language at the barrier, Run the first contact by species pair, or Settle in and check on welfare for weeks, following each step in order makes the difference between guesswork and reliable results, with practical guidance from Howcompass Pets Desk.

How do you introduce a New Pet to a Resident Pet Without Fights?

Howcompass | How to Introduce a New Pet to a Resident Pet Without Fights

According to Howcompass Pets Desk, there are 5 key stages to master: Prepare the house before the animals can see each other, Trade scent for several days before any sight, Read the body language at the barrier, Run the first contact by species pair, Settle in and check on welfare for weeks. Bring a second animal home without a fight: a separate base room, days of scent work before sight, a barrier introduction read through body language, and species-specific rules for cats, dogs, rabbits and fish.

Method1

Prepare the house before the animals can see each other

2Howcompass

Set up a separate base room with its own everything

Choose a quiet room with a door that closes and stock it with the newcomer's own bed, food, water, tray or litter area, toys and hiding places before the carry box ever comes in. The resident keeps free run of the rest of the house, so neither animal has to defend a resource it did not choose and the newcomer can settle without being watched. Keep the two bowls, two beds and two sets of toys genuinely separate, because shared water dishes and chew items are the first thing that produces a stand-off. The settling routine for a new puppy or kitten covers the same first-week logic for a single animal, and the base room is where all of it happens before any introduction is attempted.^[1]

Write the pair's timeline down: date of first bedding swap, first gate sight, first open-door session. Recovery from a setback is far easier with a map.
Howcompass Pets Desk notes that checking your progress before moving on to Step 2 prevents the most common beginner mistakes.[2]✓

3Howcompass

Barrier-proof the gap under the door

Fit a stair gate or a door barrier and check the gap for what can pass through it: a paw, a muzzle, a kitten's head, a rabbit's foot. Roll a towel along the base of the door if the gap is more than a couple of centimetres, since a resident cat that can put a paw under and swat at a newcomer through the gap will teach the newcomer that the door is not safe, and a curious dog nose will shove a barrier aside. The barrier needs to be tall enough that a cat cannot vault it and sturdy enough not to bow when a dog leans on it, and the room behind it needs two exits so no animal is cornered. Fix any skirting gaps and check the garden fence too if outdoor cats are involved, using the same sealing logic as closing a draughty window frame with removable silicone so the closure is reversible and leaves no hole behind.^[2]

Two handlers are worth more than any piece of equipment, because one person cannot manage a lead and a cat's exit route at the same time.
Have your flat collar or harness and a 1.5 metre lead per dog within reach before starting this step so you do not have to pause mid-process.[3]✓

4Howcompass

Get the health administration finished first

Complete vaccinations, current parasite treatment and microchip registration for both animals before any contact, and ask your vet whether the newcomer needs a faecal test or a health screen. A new animal from a rescue or a breeder may be carrying ringworm, intestinal parasites, or the carriers of feline infectious diseases that a vaccinated-but-untested resident cat has never met, and an introduction that starts with a shared water bowl can become a veterinary case. Cats should be tested for the infectious diseases your vet considers relevant to your area before mixing with a resident cat, and dogs should be up to date on the vaccinations and worming the practice recommends. The Dogs Trust guidance on bringing a new dog home sets out that settling period, and registration details matter for the reasons given in the pet care advice in this category: a lost, newly homed animal is found by its chip, not by its story.^[3]

Keep a jar of very high-value food by every door you use for sessions; the reward has to be immediate to be useful.
Never restrain a cat while an unfamiliar dog approaches, and never punish a growl or hiss: the restrained cat scratches the dog's nose or eye and panics into a bite, while punishing the warning deletes the only signal that a fight is coming.[4]✓

5Howcompass

Protect the resident's routine before anything else

Feed, walk and play with the resident animal at its usual times, with its usual person, and schedule the newcomer's care around that rather than replacing it. Resource loss is what turns a tolerable situation into a fight, and a resident dog that has been walked every morning at seven for four years will take the new cat far better if the walk still happens at seven. Give the resident deliberate one-to-one time in the room away from the newcomer every day, ideally with the high-value thing it likes best, and let it keep its bed and its sofa place during the first weeks. The household wind-down routine in this library works on the same principle for children: predictability first, novelty second, and never both at the same moment.^[4]

Baby gates with a small cat door let a cat move freely through the house while the dog stays on one side, which speeds everything up.
Have your two pet beds and two hiding boxes, one per animal within reach before starting this step so you do not have to pause mid-process.[5]✓

6Howcompass

Remove every shared high-value item

Pick up bowls, beds, rawhides, toys, shoes and the good sofa cushion for the duration of the introduction, and feed both animals with doors shut. Resource guarding is the most common cause of a sudden fight between animals that had been behaving, and it happens over exactly the three things left out: food, a chew, and a sleeping place near a person. Keep bones and long-lasting chews entirely off the floor during this period, since they are worth fighting for in a way that a rubber toy is not, and never leave two animals alone together with anything they have both previously shown interest in. Impulse control around food is trained separately and in advance, and the leave-it drill in this library is the version that transfers well to a hallway with a cat walking past a bowl.^[5]

Wash your hands after handling each animal during the early weeks, so you are not carrying one animal's scent onto the other by accident.
Howcompass Pets Desk notes that checking your progress before moving on to Step 6 prevents the most common beginner mistakes.[6]✓

Method2

Trade scent for several days before any sight

7Howcompass

Swap the bedding once a day for a week

Move each animal's blanket or bed cushion into the other's room every day, so both sleep in the other's smell without ever meeting. Scent is the sense that builds the strongest first impression in both cats and dogs, and a bed that already carries the newcomer reduces it from an intruder to a fact of the household before the eyes are involved. Expect the resident to sniff intensely, urinate slightly on it, carry it off or ignore it; growling at the cushion is normal information, and it is worth noting how intense the reaction is, because a resident that will not go near the bedding is telling you the pace needs to slow. Wash nothing of the exchanged items during this stage, since the whole point is the smell, and follow the wider welfare principle in this category that the animal sets the speed, not the calendar.^[6]

Expect plateaus. Two weeks of no visible progress after a good first month is normal, and the animals are learning more than you can see.
A cat that has not eaten for two days, particularly an overweight cat, risks a life-threatening liver condition; a food-refusing cat is a veterinary appointment, not a wait-and-see.[7]✓

8Howcompass

Carry cheek scent between the two animals

Rub a clean soft cloth gently over the corners of each cat's cheeks and along the base of the tail, then place that cloth near the other animal's food bowl or resting area for a few minutes a day. Those glands deposit the facial pheromones a cat uses to mark its own environment as familiar, so a cloth carrying the newcomer's cheek scent presented next to meals teaches the resident that this smell appears alongside good things. Do it in short sessions, and let the animal investigate on its own terms rather than pushing the cloth into its face, which reads as an attack. Dogs receive the same treatment with a cloth wiped over the neck and flank, and vertical scratchers and perches are useful here because the resident deposits its own scent while rubbing, the behaviour the climbing shelf guide relies on when it puts posts at cat height.^[7]

Write the pair's timeline down: date of first bedding swap, first gate sight, first open-door session. Recovery from a setback is far easier with a map.
Howcompass Pets Desk notes that checking your progress before moving on to Step 8 prevents the most common beginner mistakes.[1]✓

9Howcompass

Swap the rooms behind closed doors

Once both animals are relaxed with the other's bedding, put the resident in the newcomer's room and the newcomer in the resident's space for twenty to sixty minutes, with the doors shut, and repeat daily. Exploring an empty room at full intensity is how an animal gathers information without risk, and a cat that has walked through a dog's bed and back twice before the meeting is a cat that has far less to investigate when the dog is present. Keep the sessions short at first, clean nothing afterwards, and do not let the two animals see each other through a window during the swap, since a visual contact at this stage defeats the purpose. This room-rotation habit is the fish version of quarantine separation and the dog version of the base room: information without contact.^[1]

Two handlers are worth more than any piece of equipment, because one person cannot manage a lead and a cat's exit route at the same time.
Have your litter trays placed away from the shared door within reach before starting this step so you do not have to pause mid-process.[2]✓

10Howcompass

Feed on either side of the closed door

Put each animal's food bowl one to two metres from the shared door, on its own side, and move the bowls twenty-five centimetres closer to it at each meal while both still eat calmly. Eating is the most reliable positive emotion in a household, and pairing the sound, movement and smell on the other side of that door with a full stomach is the single most useful thing you can do before an introduction. If either animal will not eat, refuses to sit near the door, or growls over its bowl, you have moved too fast: take the bowls back a step and stay there for several meals. The International Cat Care advice on introducing cats describes this door-feeding progression in the same order, and the timing skills from the puppy sit lesson help you reward calm at the door rather than excitement.^[2]

Keep a jar of very high-value food by every door you use for sessions; the reward has to be immediate to be useful.
A rabbit housed where a dog or cat can reach it can be killed outright or stressed into a fatal gut stall; the enclosure must be a physical barrier, not a courtesy.[3]✓

11Howcompass

End every session while both animals are still loose

Keep scent and door sessions to five or ten minutes, two or three times a day, and finish the session one step before either animal looks tense. A short, boring, successful repetition builds tolerance; a long session that ends in a stiff stare, a hiss or a lunge is remembered and makes the next one harder, which is why the plan is measured in weeks rather than in one ambitious afternoon. Watch for the loose-body tell in both species: soft corners of the mouth, a slowly wagging low tail in a dog, ears forward and unhurried grooming in a cat, and a normal start on the food. If you cannot get a calm five minutes, the answer is to go back to bedding swaps for another three days rather than to push through, as the settling advice for a new puppy or kitten also recommends when a young animal is overwhelmed.^[3]

Baby gates with a small cat door let a cat move freely through the house while the dog stays on one side, which speeds everything up.
Have your notebook or phone note for a dated introduction log within reach before starting this step so you do not have to pause mid-process.[4]✓

Method3

Read the body language at the barrier

12Howcompass

Learn the loose signals and the stiff ones in a dog

Before you open anything, be able to name what calm looks like: a soft curved body, low loose tail, an open mouth, ground sniffing, and a dog that turns its head away. Those self-handling behaviours, where a dog sniffs the floor, shakes off or looks aside, are the ones that predict a safe introduction, and a dog that does them is choosing de-escalation. The warning pattern is a body that goes still and upright, weight leaning forward, mouth closed, ears forward, tail raised and vibrating in small quick motions, hackles raised along the shoulders, and a hard fixed stare that does not blink; that combination means you are one second from a chase, not one second from a greeting. The same reading applies on walks, and the impulse-control leave-it session is the fastest way to give a dog something to do instead of staring.^[4]

Wash your hands after handling each animal during the early weeks, so you are not carrying one animal's scent onto the other by accident.
Howcompass Pets Desk notes that checking your progress before moving on to Step 12 prevents the most common beginner mistakes.[5]✓

13Howcompass

Learn the fear signals in a cat

A cat that is frightened rather than annoyed shows pinned ears, a flattened body low to the floor, a tucked or puffed tail, dilated pupils, skin twitching along the back, and a low growl or hiss. A hissing cat at a gate is not the problem; hissing is a cat's honest statement of distance needed, and a cat that can hiss and then walk away to a perch is a cat with options. The dangerous situation is the silent one: a cat pressed flat behind furniture, refusing food, not using its tray, or over-grooming a patch bald, because that animal is coping by shutting down and will not warn you before it lashes out. International Cat Care's body language guide walks through these postures, and the household fix is the same every time: give the cat a route up and out, as described in the vertical perch build.^[5]

Expect plateaus. Two weeks of no visible progress after a good first month is normal, and the animals are learning more than you can see.
Cat bites and scratches look trivial and infect deeply within twenty-four hours; any puncture, any eye or nose wound and any bite that breaks skin needs same-day veterinary attention.[6]✓

14Howcompass

Never punish a growl

Do not shout, correction-leash, spray or otherwise punish either animal for growling, because you are deleting the only warning you have. A growl is distance-seeking behaviour, and an animal that has learned that growling brings punishment either stops warning and bites without sound, or becomes anxious about the other animal's mere presence. Respond instead by increasing the gap: step back, close the door, feed further apart, and shorten the next session. A dog that lunges and barks at a barrier while a cat hisses from distance is a pair that is not ready, which is information, not disobedience, and the same humane rule governs the grooming sessions in this library where a frozen or snapping animal is a signal to stop and to investigate pain, not to hold on harder.^[6]

Write the pair's timeline down: date of first bedding swap, first gate sight, first open-door session. Recovery from a setback is far easier with a map.
Howcompass Pets Desk notes that checking your progress before moving on to Step 14 prevents the most common beginner mistakes.[7]✓

15Howcompass

Put the dog on a loose lead with a second handler

Fit a flat collar or harness and a one-and-a-half-metre lead, hold it with slack, and have a second adult present to manage the cat's exits rather than to hold it. A taut lead transmits your tension straight into the dog's neck, raises arousal and pulls the dog forward into a stare, so keep the lead loose and let your body weight do the blocking; the length is short enough to intervene and long enough that the dog can move its head naturally. The second person's job is not to restrain the cat, which removes the cat's ability to leave, but to make sure the route to a perch or another room is open and known. Ask for fifteen seconds of calm sitting at the gate, reward it, and release, which is exactly the behaviour built in the puppy sit lesson and far more useful than hoping.^[7]

Two handlers are worth more than any piece of equipment, because one person cannot manage a lead and a cat's exit route at the same time.
Have your separate food and water bowls for every animal within reach before starting this step so you do not have to pause mid-process.[1]✓

16Howcompass

Interrupt fixation before it becomes a stalk

The moment a dog stares without blinking, cut the view with your body, say the marker word calmly and pay for turning away, rather than waiting for a lunge. Fixed looking at a moving cat practises and therefore strengthens the hunting sequence, which is why handlers of terriers, sighthounds and herding breeds are strict about never allowing a cat to be watched in silence; three minutes of unbroken staring at a gate does more damage to an introduction than a week of well-managed sessions. Redirect to a nose task, a scatter of dry food on the floor or a chew, all of which lower arousal, and end the session on the redirect rather than on the stare. If a dog will not disengage at distance, keep the door shut and work at greater remove for another week, following the welfare advice in this category rather than an online rule about how long an introduction should take.^[1]

Keep a jar of very high-value food by every door you use for sessions; the reward has to be immediate to be useful.
Chocolate, xylitol, grapes, raisins, onion, alcohol and lilies are all hazards during a chaotic settling period, and two animals competing for food will eat things neither would normally touch.[2]✓

Method4

Run the first contact by species pair

17Howcompass

Cat and dog: let the cat choose the moment

Open the door with the dog on a loose lead, the room large, the exits clear and three or more escape routes up, and wait for the cat to decide whether to enter. Do not carry the cat into the room, do not chase it to be friendly, and do not let the dog approach in a straight line; a cat that walks in, sits at distance, watches and leaves is having an excellent first meeting. Keep the contact to three or five minutes with a calm dog and reward the dog for every glance away from the cat, then close the separation again and repeat later the same day or the next. International Cat Care's introduction guidance recommends exactly this slow, retreat-friendly progression, and the household vertical perch and climbing shelf is what makes the escape routes real rather than theoretical.^[2]

Baby gates with a small cat door let a cat move freely through the house while the dog stays on one side, which speeds everything up.
Have your high-value treats kept by every door used for sessions within reach before starting this step so you do not have to pause mid-process.[3]✓

18Howcompass

Never restrain a cat in front of a dog

Do not hold a cat in your arms, on a lap, or pinned against furniture while an unfamiliar dog approaches, because a cat that cannot escape defends itself with claws and teeth and the dog will react. The classic injury in a first meeting is a dog's nose or eye scratched by a held cat, followed by a dog that has now learned that cats hurt, and both halves of that lesson are hard to undo. A frightened, restrained cat also panics into a bite or a frantic climb, and the person holding it gets caught in between. Let the cat loose with an open route instead, treat the dog for stillness, and if the dog is a genuine chase risk, keep the door shut and manage the pair physically apart for weeks while you build the leave-it and settle behaviours that make contact safe later.^[3]

Wash your hands after handling each animal during the early weeks, so you are not carrying one animal's scent onto the other by accident.
Howcompass Pets Desk notes that checking your progress before moving on to Step 18 prevents the most common beginner mistakes.[4]✓

19Howcompass

Dog and dog: walk in parallel before you introduce face to face

Take both dogs out on separate leads with separate handlers and walk parallel to each other with three metres of space between the lines, changing which side each dog is on every few minutes. Head-on approach in a doorway is what produces a fight between two otherwise friendly dogs, because face-to-face posturing has no exit and the greeting is over before it starts; parallel walking lets them read each other's movement without committing. Shorten the distance gradually over several walks as both dogs stay loose and bouncy, and watch for the good signs: curved bodies, play bows, loose open mouths, and dogs that check back with their people. End each walk with a break apart, and keep the first home meeting on neutral territory with the resource items already put away, exactly as the new dog settling plan from Dogs Trust suggests. Keep treats in a pouch on the lead hand so the reward lands while both dogs are still loose, using the marker timing taught in the puppy sit lesson, and finish the walk while both are still able to behave.^[4]

Expect plateaus. Two weeks of no visible progress after a good first month is normal, and the animals are learning more than you can see.
Never restrain a cat while an unfamiliar dog approaches, and never punish a growl or hiss: the restrained cat scratches the dog's nose or eye and panics into a bite, while punishing the warning deletes the only signal that a fight is coming.[5]✓

20Howcompass

Cat and cat: rotate rooms for a week, then meet at a gate

For two cats, continue the room rotation and door feeding for at least seven to ten days, then allow a short sight at a gate or a cracked door with food on both sides and a hide box in the open room. Cat-cat introductions fail more often than cat-dog ones because a resident cat is defending a territory it cannot leave, so the newcomer's scent must become ordinary before the newcomer is visible, and both cats need exits and elevation in the meeting room. Expect hissing, a swat or a growl, and keep the session under five minutes; a stalemate where both cats ignore each other is a better result than a friendly approach, because indifference does not have to be sustained. If one cat stalks the other around the clock after contact, separate them again and rebuild through the litter and resource plan in this library, since ambush at the tray is what turns tension into avoidance.^[5]

Write the pair's timeline down: date of first bedding swap, first gate sight, first open-door session. Recovery from a setback is far easier with a map.
Howcompass Pets Desk notes that checking your progress before moving on to Step 20 prevents the most common beginner mistakes.[6]✓

21Howcompass

Dog or cat with a rabbit: treat the enclosure as a hard barrier

House the rabbit where a dog or cat cannot reach it when you are not in the room, with a latched run, solid walls rather than wire a paw can bend, and a raised hide box inside. This pairing is predator and prey, and a rabbit terrified by a paw through the mesh will stop eating, and a stopped-eating rabbit can develop a fatal gut stall within a day or two; equally, one opportunistic snap from a terrier-type dog can kill outright. Supervised garden time with the rabbit in a secure ground run and the dog on a lead is the most contact most rabbits should ever get, and a rabbit that thumps its foot, presses flat against the ground or bolts is telling you the distance is too small. Build the housing to that standard from the start, as the hay-focused rabbit habitat guide sets out, and never leave a dog alone in the room with an open run.^[6]

Two handlers are worth more than any piece of equipment, because one person cannot manage a lead and a cat's exit route at the same time.
Have your rabbit or guinea pig run with a latch and solid walls within reach before starting this step so you do not have to pause mid-process.[7]✓

22Howcompass

Cat with a fish tank: secure the lid and the stand

Fit a mesh or glass lid that the cat cannot push aside, weigh down anything the cat can climb on near the glass, and dry the rim after every visit so a wet paw does not invite a drink. A cat will absolutely put a paw into an aquarium, and the risk is not the loss of two or three fish but the contaminated water, the knocked lid, and the fish that die of stress from being chased along the glass for an hour. Keep the room door closed when the cat is free, wipe any spill immediately, and check the stand for wobble every week since a leaning cat can shift a filled tank. The lid, freeboard and stability points are covered in the aquarium setup routine here, and if the cat is drawn to the water, give it a running bowl of its own away from the tank, which usually beats the fish.^[7]

Keep a jar of very high-value food by every door you use for sessions; the reward has to be immediate to be useful.
A cat that has not eaten for two days, particularly an overweight cat, risks a life-threatening liver condition; a food-refusing cat is a veterinary appointment, not a wait-and-see.[1]✓

23Howcompass

Keep early face-to-face sessions under five minutes

Run the first contacts with a timer on your phone, three to five minutes long, with high-value food in both hands, and separate the animals before either makes a mistake. Short repetition is what builds the association; two calm five-minute meetings a day for a fortnight achieve more than one hopeful half-hour, and the moment one animal lunges, hisses or freezes, the session is over and the separation goes back up. Feed both at the same time on opposite sides of the doorway afterwards, which ends the session on a positive and predictable note, and keep your own breathing and voice low, since animals read your arousal instantly. For the dog, nose work and chewing are the settling tools, and the coat-to-nails grooming session structure uses exactly the same fifteen-minute-with-settles arithmetic that keeps any handling calm.^[1]

Baby gates with a small cat door let a cat move freely through the house while the dog stays on one side, which speeds everything up.
Have your camera or phone for session photographs within reach before starting this step so you do not have to pause mid-process.[2]✓

Method5

Settle in and check on welfare for weeks

24Howcompass

Supervise everything until weeks of calm have passed

Do not leave the pair alone together until they have been relaxed in each other's presence for at least two to four weeks of supervised time, and keep the separation in place overnight far longer. A dog that ignores a cat for a fortnight can still chase it once, on a day the cat runs, and chase behaviour is self-rewarding: the practice is the danger, not the intention. Until then, the door shut, the gate in place and the rabbit indoors are your normal state, not a failure, and the same applies to food, beds and the good sofa. Setbacks are normal and are not a reset to zero; go back one step in the sequence for a few days, and if you cannot find a working distance for a dog that will not disengage, ask your vet for a referral to a qualified behaviourist rather than trying to force familiarity, a stance the advice pages in this category take across every species.^[2]

Wash your hands after handling each animal during the early weeks, so you are not carrying one animal's scent onto the other by accident.
Howcompass Pets Desk notes that checking your progress before moving on to Step 24 prevents the most common beginner mistakes.[3]✓

25Howcompass

Watch the resident animal for stress, not just the newcomer

Check both animals weekly for appetite change, hiding, weight loss, litter tray avoidance, over-grooming, destructive scratching and sleeping in odd places, and treat those as data rather than bad manners. Stress in a resident cat often shows up as a urinary problem or a bald patch on the belly long before any overt conflict, and stress in a dog shows as pacing, whining, house-soiling and refusal of its usual walk. Weigh both animals monthly on a baby scale or by holding-and-subtracting, and keep the observations in one note so you can see a trend instead of arguing with yourself about whether things are worse this week. Keeping a two-week log of the same variables is the habit that turns a vague worry into a veterinary history worth paying for.^[3]

Expect plateaus. Two weeks of no visible progress after a good first month is normal, and the animals are learning more than you can see.
A rabbit housed where a dog or cat can reach it can be killed outright or stressed into a fatal gut stall; the enclosure must be a physical barrier, not a courtesy.[4]✓

26Howcompass

Have bite and scratch wounds seen the same day

Any puncture from a cat's tooth or claw, any wound on the nose, eyelid or genitals, and any dog bite that breaks the skin should be examined by a veterinarian on the day it happens, not the following morning. Cat mouths carry bacteria that produce deep abscesses under seemingly tiny holes, and a small puncture that looks fine at eight in the evening is often a swelling, feverish, painful wound by day three; antibiotics started early are the difference between a week of tablets and a surgical drain. Rinse a superficial graze with clean lukewarm water and do not use household disinfectants, hydrogen peroxide or alcohol on open tissue, which damage the healing surface as much as they clean it. For a genuinely shallow scratch with no puncture, follow the minor cut and graze routine in this library, keep it clean and dry, and still call the practice if the area reddens, the animal limps, or the wound swells.^[4]

Write the pair's timeline down: date of first bedding swap, first gate sight, first open-door session. Recovery from a setback is far easier with a map.
Howcompass Pets Desk notes that checking your progress before moving on to Step 26 prevents the most common beginner mistakes.[5]✓

27Howcompass

Feed separately and end the meal before contact

Keep food bowls in different rooms with doors shut for the whole settling period, pick up the bowls after fifteen to twenty minutes, and never let two animals eat from the same dish to build goodwill. Bowl guarding is the fastest route to a serious injury in a household of two dogs or two cats, and the food that seems innocent on day one becomes the thing one animal will fight for by day ten. Hand-feed the first positive coexistence instead: one person, one animal, high-value food at a comfortable distance, with the door between them or the dog on a loose lead. Wash bowls daily, keep dry food sealed and dry, and remember that a dog which has eaten the cat's food can be ill from it, so store cat food where a dog cannot reach, the same habit that keeps children's kitchen ingredients safe around a busy kitchen. The poison information list kept by the ASPCA is worth one read for the foods that must never be shared at all.^[5]

Two handlers are worth more than any piece of equipment, because one person cannot manage a lead and a cat's exit route at the same time.
Have your two pet beds and two hiding boxes, one per animal within reach before starting this step so you do not have to pause mid-process.[6]✓

28Howcompass

Never use fear, deprivation or a chance to sort it out

Do not spray, shout, collar-jerk, withhold food, confine an animal in the dark for days, or leave two unfamiliar animals shut in a room to work it out between themselves, because every one of those methods makes the next meeting worse. Letting them fight produces either an animal that is injured and frightened or one that has rehearsed and mastered chasing, and the household afterwards spends its months on separation anyway, with less trust from both animals. Deprivation of food, water, litter access or human contact is a welfare failure, not a training tool, and physical corrections applied near the other animal teach the animal to be anxious about the other animal's presence. The humane alternative is boring and works: distance, doors, scent, food, and slowly closing the gap over weeks, always ending a session while the animals are still comfortable, and the RSPCA's welfare guidance for cats and for dogs both frame the introduction around that need for control and choice. Record what you changed and what each animal did next in the same note, the reviewable-planning habit that makes a two-week sleep and energy log work for people.^[6]

Keep a jar of very high-value food by every door you use for sessions; the reward has to be immediate to be useful.
Cat bites and scratches look trivial and infect deeply within twenty-four hours; any puncture, any eye or nose wound and any bite that breaks skin needs same-day veterinary attention.[7]✓

29Howcompass

Escalate to a veterinary or behaviour consult on clear triggers

Call your veterinary practice for any of the following: an animal refusing food for more than twenty-four hours, a cat that has not eaten for two days, repeated frantic escape attempts, an injury of any size, a dog that will not disengage from staring, or aggression that escalates across three sessions. A cat that stops eating is not merely upset; a cat that does not eat for two or three days, especially an overweight one, is at risk of a serious liver condition that needs treatment rather than patience, and a frightened cat that has not used its tray for twenty-four hours needs to be checked. Ask the practice for a referral to a clinical behaviourist and, while you wait, put the separation back to the last step that worked, keep the routine predictable, and take photographs and notes of each session so the consultant has a timeline rather than impressions. The same escalation logic runs through the health guides in this library: early professional input is cheaper, kinder and shorter than a rescue attempt at the end.^[7]

Baby gates with a small cat door let a cat move freely through the house while the dog stays on one side, which speeds everything up.
Have your a towel or door-snake for gaps under doors within reach before starting this step so you do not have to pause mid-process.[1]✓