Why has my dog or cat stopped eating?
A single skipped meal in a bright pet is often minor — but a cat that won't eat needs attention far sooner than a dog.
Appetite loss (anorexia) is a non-specific sign of many problems. Contact a vet the same day — or sooner — in these situations:
- A cat that has eaten nothing for about 24 hours (sooner if overweight, diabetic, a kitten, or also not drinking)
- Any pet not eating AND lethargic, vomiting, or with yellowing of the gums/eyes (jaundice)
- A puppy or kitten refusing food, or a pet with a known illness
- Not eating together with a painful mouth, drooling, or difficulty swallowing
A pet stops eating for reasons ranging from a minor upset or fussiness to nausea, dental pain or serious illness. The species matters: a dog can usually manage a skipped meal, but a cat that stops eating — especially an overweight one — can develop a dangerous liver condition (hepatic lipidosis) within a few days, so cats need veterinary attention much sooner. Never force-feed; instead, find out why.
- Appetite loss is a sign of many possible problems, not a diagnosis.
- Cats are the priority: a cat not eating for ~24 hours warrants a vet call.
- In cats, prolonged not-eating risks hepatic lipidosis (fatty liver), which can be fatal.
- Don't force-feed; note water intake, energy and any vomiting for your vet.
What loss of appetite means
Not eating — full anorexia (nothing) or partial (eating far less) — is one of the most common signs of illness in pets, precisely because almost anything that makes an animal feel unwell can switch off appetite: nausea, pain, fever, dental problems, stress, or disease in any organ system.
In cats there's an added danger. When a cat stops eating, the body mobilises fat faster than the liver can process it, which can lead to hepatic lipidosis (fatty liver) — the Cornell Feline Health Center notes that a sustained loss of appetite can seriously affect a mature cat within as little as 24 hours, and for a very young kitten even 12 hours of not eating can be dangerous. This is why 'wait and see' is the wrong plan for a cat.
Common causes to consider
These are categories a vet thinks through — not a diagnosis of your pet:
- Nausea or GI upset — an unsettled stomach, infection or something eaten.
- Dental or mouth pain — a sore tooth, ulcer or object stuck in the mouth.
- Pain anywhere — pets in pain often go off food.
- Systemic illness — kidney, liver, pancreatic, hormonal or other disease.
- Stress or environment — new home, new pet, travel, or heat.
- Food factors — a disliked new food, or a fussy eater (a diagnosis of exclusion).
- Medication — some drugs reduce appetite.
Dogs vs cats
Dogs can usually skip a meal and be fine if they're otherwise bright, drinking and behaving normally — see a vet if it lasts beyond 24–48 hours or comes with other signs. Cats are different and more urgent: a cat not eating for around 24 hours should prompt a vet call, and overweight cats, kittens, diabetic or already-ill cats need to be seen sooner. Jaundice (a yellow tinge to the gums, ears or eyes) in a cat that isn't eating is a red flag.
In hot weather, pets may eat a little less at the peak of the day — that alone, in a bright, active pet, isn't the same as true appetite loss. What isn't normal is a genuine refusal of food with dullness, vomiting or hiding. Access to a vet can be harder in some areas, so for cats especially, don't delay the first call. If you change brands or move between home food and packaged food, do it gradually so a fussy refusal isn't mistaken for illness.
What to check, and what you can safely do
Before and during a vet call, it helps to note:
- Nothing at all, or just eating less — and for how long
- Water intake — drinking normally, or not
- Energy and behaviour — bright, or dull and hiding
- Any vomiting, diarrhoea, drooling or bad breath
- Gum and eye colour — any yellow tinge (jaundice)
- Whether the mouth seems sore, or swallowing looks difficult
- Recent changes — new food, travel, new pet, medicines
Safe to do
- Offer a small amount of a favourite, palatable food; gently warming wet food can help.
- Make sure fresh water is always available.
- Reduce stress — a calm, quiet feeding spot away from other pets.
- For cats especially, call your vet early rather than waiting.
- Write down when your pet last ate and any other signs.
Do not
- Force-feed or syringe food against your pet's will — this can be dangerous and stressful.
- Let a cat go days without eating in the hope it 'sorts itself out'.
- Give human appetite stimulants or medicines without veterinary advice.
- Assume it's simple fussiness if your pet is also dull, vomiting or hiding.
- Suddenly switch foods when your pet is already unwell.
When to see a veterinarian
Monitor (dogs): a bright dog that skips one meal but drinks and behaves normally — offer food again and watch.
Same day: any cat not eating for about 24 hours; a dog not eating beyond 24–48 hours; a kitten or puppy refusing food; or not eating alongside lethargy, vomiting, drooling or a painful mouth.
Urgent / emergency: a pet that is collapsed or very weak, a cat with jaundice, or not eating with a bloated painful belly or repeated vomiting.
What the vet may check
Your vet will examine your pet — including the mouth and teeth — assess hydration and body condition, and ask about the timeline. Depending on findings they may suggest blood tests, urine testing or imaging to look for an underlying cause, and support feeding safely if needed. Identifying and treating the reason for not eating is the priority, particularly in cats.
Frequently asked questions
How long can a cat safely go without eating?
Not long. A cat that eats nothing for around 24 hours should prompt a vet call, and overweight, diabetic or very young cats sooner. Prolonged not-eating risks hepatic lipidosis, a potentially fatal liver problem — so cats are treated more urgently than dogs.
My dog skipped one meal but seems fine — should I worry?
Usually not, if your dog is bright, drinking and behaving normally. Offer food again at the next meal and watch. See a vet if the refusal lasts beyond 24–48 hours or other signs appear.
Should I force-feed my pet?
No. Forcing food can be dangerous, stressful and counterproductive. If your pet won't eat, the safer route is to find out why with your vet, who can support feeding properly if needed.
Can stress stop a pet eating?
Yes — a new home, a new pet, travel or upheaval can all reduce appetite. But stress is a diagnosis of exclusion, especially in cats, so rule out illness first.
My cat's gums look a bit yellow — what does that mean?
A yellow tinge (jaundice) in a cat that isn't eating is an important warning sign that needs prompt veterinary attention. Don't wait.
Could a bad tooth be the reason?
Very possibly. Dental pain, mouth ulcers or an object stuck in the mouth are common, under-recognised reasons pets go off food — your vet will check the mouth as part of the exam.
Sources
- SourceCornell Feline Health Center — Anorexia (loss of appetite in cats). vet.cornell.edu
- SourceVCA Animal Hospitals — Hepatic Lipidosis (Fatty Liver) in Cats. vcahospitals.com
- SourceUniversity of Illinois College of Veterinary Medicine — Hepatic Lipidosis When Cats Don't Eat. vetmed.illinois.edu