My cat is not eating: what now, and how do you tell a cat is sick?

Not eating, or eating much less than usual, is what vets call anorexia or loss of appetite. It is a sign of many different problems, not a disease by itself. So the vet looks for the cause as well as getting the cat eating again. Loss of appetite is one of the most common reasons owners take a cat to the vet.

Hunger and appetite are not the same. A cat can be hungry and still not want to eat. Vets also separate a cat that does not want food from one that wants it but cannot pick it up, chew or swallow it, usually because of mouth pain.

Most cats graze through the day on small meals. That is why eating less than usual is usually a sign that something is wrong, not a mood. Partly eating counts too: a cat that nibbles a little is not necessarily eating enough, and a cat that takes treats but leaves its meals may be too unwell for a full meal.

In a home with more than one cat, or a dog that eats the cat's food, it can be hard to see that one cat has stopped eating. Watch who eats what, and weigh the cat if you are unsure.

There is no safe number of days to wait. Cats are not like dogs, which can go days without food with few signs. A cat that stops eating can get into trouble within a day or two. A veterinary school says that in a mature cat a loss of appetite can seriously affect health after as little as 24 hours, and a kitten under six weeks old can be in lethal danger after only 12 hours.

Vets and welfare groups differ a little on when to call: some say after about a day, others after two days. They agree that a cat that has eaten nothing for about a day needs a vet, and that kittens, older cats, overweight cats and cats with a known illness should not wait that long. So this page says: call after about 24 hours, go now after two days.

Not drinking makes things worse. A cat that is not eating and also not drinking can dehydrate quickly and needs a vet the same day. A cat that drinks but does not eat is still on the same clock for fatty liver, so drinking does not make waiting safe.

In hospital, vets consider feeding support when an ill cat has eaten too little for about three days or has lost about 10 percent of its body weight. That is a threshold for vets, not a time to wait at home.

When a cat stops eating, its body breaks down fat to use as fuel. The liver cannot process fat that fast, so it builds up inside the liver cells and the liver starts to fail. This is called fatty liver, or hepatic lipidosis. It is the most common acquired liver disease in cats that can be fatal, and it can happen at any age, from about three months to 25 years. Overweight cats are at much higher risk.

Fatty liver most often follows several days of not eating, but it can begin sooner, and eating only a little can still lead to it. In more than 9 out of 10 cases it follows another problem, such as an illness, pain or stress that made the cat stop eating. The two feed each other: the sicker the liver gets, the more nauseous and off food the cat is.

Signs include a cat that avoids its bowl, drools, vomits, loses weight, seems dull or weak, and later turns yellow in the gums, ears or whites of the eyes (jaundice). Fatty liver itself is not painful, but the illness behind it may be.

Without prompt treatment, fatty liver is likely to be fatal. With treatment many cats recover, and the outlook is best for cats seen early. Published figures differ between hospitals, from roughly 6 to 9 in 10 cats surviving; treat that as a rough guide only. Recovery takes weeks, not days, and usually means tube feeding. Cats that survive an episode rarely have it again.

Mouth and tooth pain is one of the most common reasons. Gum disease, broken teeth, tooth resorption, mouth ulcers and abscesses can all make chewing hurt. Tooth resorption affects an estimated 20 to 60 percent of cats, and a single broken tooth crown can put a cat off its food for a day or three. Signs are pawing at the mouth, dropping food, chewing on one side, drooling, eating only soft food, bad breath, or walking up to the bowl and backing away. Some cats with sore teeth keep eating, so a normal appetite does not rule it out.

Nausea and stomach or gut trouble: vomiting, diarrhoea, constipation, inflammation, pancreatitis, or a swallowed object that blocks the gut. A cat that walks up to the bowl, sniffs and walks away may be nauseous. A swallowed string or hair tie is a surgical emergency.

Illness elsewhere in the body: kidney disease, diabetes, an overactive thyroid, liver disease, heart disease, infection with fever, anaemia and cancer can all begin with a cat that eats less. Kidney disease causes nausea and mouth ulcers because waste builds up in the blood. Pain of any kind lowers appetite, including joint pain, an injury, or back pain that makes reaching the bowl hard. Pain is easy to miss in cats, and eating less may be the only sign.

A blocked nose or loss of smell, for example from cat flu, makes food less appealing, because smell drives a cat's appetite. Poison can also show up first as a cat that suddenly refuses food, often with drooling, vomiting or tremors. Lilies, human medicines, antifreeze and household chemicals are examples. A hot room can also reduce appetite.

Stress and change: a move, a new pet or baby, building work, a lost companion, boarding, or being bullied at a shared bowl. Stress can make a cat stop eating for a day or two, and a cat that stays off food for longer needs a vet, not just patience. Vets rule out medical causes before blaming stress or behaviour.

Food and feeding: a sudden food change, a new bowl or a bowl moved to a new spot, stale or dirty food, a bowl so deep it touches the whiskers, or food left out all day. Cats can also refuse a food they link with feeling unwell, or with a vet or cattery stay.

Medicines and treatments can lower appetite, including some antibiotics, pain medicines and long-term anxiety medicines. Vaccines or an operation can cause a day of low appetite, but refusing food for more than 24 hours afterwards is not normal and a reason to call.

Cats hide illness well, so a cat that looks bright can still be unwell. By the time eating visibly drops, the problem may have been building for a while. A single skipped meal in a bright, active cat is often just a blip: offer a favourite food, keep the bowl clean and quiet, and watch through the day. If the cat is not eating normally again by the next day, call the vet.

Many indoor cats need little food, so truly picky eating is common. But a clear change in how much a cat eats, up or down, is worth telling the vet about, especially if it lasts more than a day or two. Eating a little is not the same as eating enough: a cat that eats a few bites for several days can slide towards fatty liver just like a cat that refuses everything.

Look at how the cat eats, not only how much. Eating much more slowly than before, chewing on one side, dropping food or swallowing kibble whole can point to mouth pain. A cat that used to empty its bowl in two minutes and now takes five has changed. Eating more than usual while losing weight can also be a sign of illness, such as an overactive thyroid or diabetes.

Weigh your cat and look at its body shape. Sudden or unexplained weight loss is always worth a vet check, even if the cat seems normal. Gradual loss is hard to see, especially in a fluffy cat, so a regular weigh-in at home helps.

Lethargy is more than sleeping a lot. A lethargic cat is hard to rouse, moves very little and ignores things it normally cares about, such as meals, play or the treat bag. A sleepy cat still responds to food and sounds.

A cat that is not eating and is also lethargic needs a vet the same day, even before 24 hours have passed. A cat that is not eating, not drinking and lethargic should go to a vet or emergency clinic now. Without fluids a cat can dehydrate fast, and without food it moves towards fatty liver at the same time.

Other red flags with this picture: hiding and refusing to come out, a cold body, pale, blue or yellow gums, sticky dry gums, repeated vomiting, breathing hard or with the mouth open, a swollen or painful belly, collapse or not responding. Dehydration clues you can report to the vet: gums that are tacky rather than moist, and skin on the shoulders that settles back slowly when gently lifted. They help judge urgency but do not replace an exam.

Fever from infection often lowers appetite; the vet checks the temperature. Never give a cat a human fever or pain medicine: paracetamol and ibuprofen are toxic to cats. Phone the vet or the emergency practice before you leave, tell them how long the cat has not eaten or drunk and what else you have seen, and ask whether to come at once.

Not eating is not just old age. In a senior cat a lost appetite is almost always a symptom with a cause that can often be treated. A senior cat that has refused food for around a day, or one that is not eating and not drinking, should be seen the same day.

Older cats more often have kidney disease, an overactive thyroid, diabetes, dental disease, bowel disease, pancreatitis, arthritis or cancer. Kidney disease affects an estimated 30 to 50 percent of cats over 15, and typical early signs are drinking and peeing more, weight loss and a slowly falling appetite. Dental disease gets more common with age and is often overlooked as a cause of decline; age alone is not a reason to skip dental treatment.

Older cats often have more than one disease at once. When one treatment does not bring the expected result, vets look for another cause. Weight loss with no other cause is a common sign of cancer in older cats. An older cat can also lose some sense of smell, and arthritis or age-related confusion can make eating harder.

International guidelines for senior cats advise a check-up every six months, even for a cat that seems healthy, with weight checked at every visit, and at least a yearly blood and urine check from about age 7 to 10. For older cats that eat little, vets advise small frequent meals and more water, for example wet food and several water bowls.

Kittens have almost no energy reserves. A kitten that misses meals can fall into low blood sugar and dehydration within hours, not days, so the adult 24-hour window does not apply. A kitten under six weeks old that has not eaten for 12 hours is at lethal risk and needs urgent veterinary care. Kittens under three months cannot control blood sugar well.

Low blood sugar in a kitten shows as weakness, wobbling, tremors, lethargy and being cold, and can end in seizures, collapse or coma. This is an emergency: phone the clinic first, then go as fast as you safely can. Do not try to feed a kitten that is cold, floppy or unresponsive; warmth, careful handling and a vet come first.

Causes include weaning, cold, intestinal parasites, infection, cat flu and simply being too busy playing to eat. A kitten that will not nurse, loses weight, is weak and cries a lot may be a fading kitten and needs a vet at once. A lethargic kitten that is not eating is always an emergency, and any kitten that refuses to eat for most of a day should be seen the same day.

Weigh a kitten daily. A kitten that is not gaining weight steadily should be checked by a vet. A new kitten in a new home may eat less on the first day from stress, but the 24-hour clock still applies.

Cats are masters at hiding pain and illness. In the wild, showing weakness made a cat vulnerable, and house cats keep the instinct. Big changes are rarely the first sign. The earliest signs are usually small changes in routine, behaviour or appetite, so knowing what is normal for your cat is the best tool you have.

Behaviour: hiding more, not coming to greet you, withdrawing from touch, lying in one position for long periods, sleeping much more, or seeming absent. A normally social cat avoiding you is more concerning than a cat napping in its usual quiet spot. Posture and movement: a hunched posture, squinting, ears turned back, no longer jumping to favourite spots, limping or reluctance to move can mean pain.

Coat: a cat that is ill often stops grooming, and its coat looks untidy, greasy or matted. Breathing: fast breathing at rest, breathing with effort, open-mouth breathing, panting or persistent coughing needs a vet; cats rarely breathe with the mouth open unless they are in serious distress. Litter box: a change there is often the first visible sign of urinary, kidney or metabolic illness. Straining, crying in the box, blood in urine or stool, peeing in odd places, much more peeing, diarrhoea or constipation all need attention. A male cat straining with little or no urine is an emergency.

Drinking much more than usual, or from unusual places, can come from kidney disease, diabetes or thyroid disease. Eating less or much more, weight loss, bad breath, dropping food or drooling belong on the list too, as does a cat that is louder or more demanding than usual for more than a day or so, grumpier or clingier. Some signs are not reliable: a dry nose alone does not mean a cat is sick, and purring does not mean it is content, because cats also purr when stressed, in pain or unwell.

Home tempting is a bridge to care, not a replacement for it. If the cat is past about a day without eating, or nothing works within a few hours, stop trying and call the vet. Write down when the cat last ate normally, how much it has eaten since and what else you have seen; the timeline helps the vet.

Smell matters: warm wet food and strong-smelling food often win over a queasy cat. Offer the food the cat already knows first; if it eats a bit of that, a recent change is the likely cause. If the cat drools, backs away or turns its head from a food, take it away. Pushing a sick cat to eat can leave it with a lasting dislike of that food.

A cat that is not eating deserves a full check: history, a physical exam with a close look at the mouth, nose, gums, heart, lungs, belly and temperature, and then tests as needed, such as blood tests, urine tests, X-rays and ultrasound. Vets also ask about food changes, home changes, medicines, litter box habits and drinking, so bring notes.

Vets treat the not-eating itself while they look for the cause: fluids if the cat is dehydrated, anti-nausea medicine, pain relief, and correction of low potassium or other mineral problems. Vets sometimes prescribe a short course of an appetite stimulant, such as mirtazapine or cyproheptadine. These are not a cure: they are unreliable in sick cats, do not treat the cause, can cause sedation or other side effects, and some are avoided in cats with liver disease. Never give one without a vet. The vet picks the medicine and the amount; this page does not.

Where a cat cannot or will not eat enough, a vet may place a feeding tube. Tubes are placed under anaesthesia, can be lifesaving even for a few days, and many cats go home with the tube. Vets prefer a tube over forcing food. Feeding a cat that has not eaten for a while has its own risks (refeeding syndrome), so restarting food is led by the vet.

Fatty liver is usually confirmed with blood tests, ultrasound and a sample of liver cells, and treated with fluids, vitamins, correction of salts and tube feeding for weeks while the cause is treated. Mouth disease is treated at the vet; for tooth resorption the only effective treatment is removing the affected teeth. If a cat sent home after a hospital stay still will not eat, take it back the next day.

Weigh your cat regularly, ideally with a baby or pet scale at home, and measure its food so you notice quickly when it eats less. Keep your cat at a healthy weight. If it is overweight, plan weight loss with your vet. Never starve an overweight cat or cut its food sharply, because sudden weight loss can trigger fatty liver.

Change food slowly, keep routines steady and reduce stress where you can. Have the teeth checked every year, with X-rays if a vet suspects resorption, and book regular check-ups, especially when behaviour, weight or eating changes. Call the vet promptly when appetite drops: fatty liver can be prevented by watching what a cat eats and getting help early.