Why is my dog not eating?

The one time limit we found in a veterinary source is VCA’s urgent care advice: have your pet seen if it has not eaten for more than 12 hours, or if it is diabetic and refuses even one meal (VCA). VCA’s wider advice is to take changes in your dog’s eating seriously and involve your vet early (VCA). The Merck Veterinary Manual and Cornell pages we read give no number of hours or days, and no source gives a separate limit for puppies.

Loss of appetite matters because it is a common sign of many illnesses, and it makes the body break down its own tissue faster (Merck). Many pet websites quote a number of days. We could not find those numbers in a veterinary source, so we do not repeat them.

Toy-breed puppies can develop low blood sugar in the first 6 months of life, which is usually managed with frequent meals of a commercial puppy food (Merck).

• Parvovirus commonly affects puppies between 6 weeks and 6 months old. Its earliest signs are lethargy, then less appetite and vomiting (Cornell).
• Any puppy with vomiting and diarrhoea should be tested for parvovirus (Cornell).
• Motion sickness, which causes nausea, is more common in young dogs (VCA).

Keep up your puppy’s vaccinations, set out in our puppy vaccination schedule, and track growth with the puppy weight calculator.

Yes. Some dogs are hungry but struggle to pick up, chew or swallow food, which VCA calls pseudo-anorexia (VCA). Dental disease is a common cause of mouth pain: over 80% of dogs over the age of three have active dental disease (VCA).

• Chewing with obvious discomfort
• Dropping food, drooling or swallowing awkwardly
• Pawing at the mouth, and bad breath (VCA)

Nausea

Nausea from any cause puts dogs off food (VCA). Look for drooling, lip licking, whining, pacing and vomiting (VCA).

Stress

A new home, visitors or a change in routine can all reduce appetite (VCA). Remove your dog from whatever is stressing them and give them a quiet place to eat. If stress is frequent, see your vet (VCA). A dog who struggles when left alone may have separation anxiety.

A new food

1. Switch over 7 to 14 days, starting with 90% old food and 10% new (VCA).
2. If appetite drops, or stools go loose, slow the change down (VCA).
3. If things do not settle within 24 hours of slowing down, call your vet (VCA).

Poor appetite is strongly associated with illness, from infection to organ disease, and can be the first sign of a serious problem (VCA). Pain anywhere in the body can also do it: decreased eating is on VCA’s list of pain signs (VCA).

• Older dogs: kidney disease becomes more common from age 5 to 6. Extra thirst comes first, and loss of appetite follows as it progresses (Merck).
• New medicines: side effects are a recognised cause of appetite loss (VCA). Call the vet who prescribed it rather than stopping it.
• Eating grass and then refusing food? See why does my dog eat grass.

A dog who keeps drinking but refuses food is still telling you something is wrong, even if they seem bright. The causes are the same as for any loss of appetite: a sore mouth, nausea, pain, stress or a food they do not like (VCA). Drinking matters in two directions.

Measure what goes into the water bowl, morning and evening, so you can tell your vet how much your dog is really drinking. That detail helps them decide how quickly to see your dog.

Once your vet has ruled out illness, or while you wait to speak to them, these steps are safe to try.

1. Warm their usual food to about body temperature, about 100°F (38°C) (VCA).
2. Offer small amounts of something very tasty, the first thing vets try too (Merck).
3. Feed in a quiet spot, away from other pets and busy rooms (VCA).
4. Never tempt with onions, garlic, grapes, raisins, fatty scraps or bones (ASPCA).

If coaxing does not work, your vet can prescribe an appetite stimulant for a short time, or in serious cases place a temporary feeding tube (VCA).

Go today for a puppy who will not eat, for any dog with lethargy, vomiting, diarrhoea or not drinking, and for a dog who has gone more than 12 hours without food (VCA). Go now if not eating comes with vomiting and lethargy (VCA). For an otherwise well adult who has skipped a single meal, call your vet to be safe: they can tell you whether to come in.

Your vet will ask about the last full meal, thirst, weight, any new food or medicine, and what your dog could have eaten. They will examine the mouth and may run blood tests. To check other behaviours, use the dog behaviour checker.

Every figure and threshold on this page comes from the veterinary sources below, and each one is linked where it is used. Where no source gives a cut-off, we say call your vet rather than invent one.