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Dog Appetite & Illness · Vet-Reviewed Guide

Dog Not Eating: Causes, When to Worry, and How Vets Help

OT
Medically reviewed by Dr. Olivier Toulza
Reviewed 8 September 2026

A dog skipping one meal is rarely a crisis. A dog that won't eat for a day or more, or won't eat while also acting sick, is telling you something worth listening to.

A dog not eating can mean anything from a minor upset to a real illness, so the context matters more than the missed meal itself. Watch for how long it's been, whether your dog is otherwise bright, and any other signs like vomiting or lethargy. Persistent appetite loss, or loss of appetite in a sick or recovering dog, needs a vet — and vets can prescribe an appetite stimulant when needed.

About Entyce (capromorelin) appetite stimulant: this is a prescription medication your veterinarian can prescribe. Read our guide, or ask us if you need help sourcing it.

Common reasons a dog won't eat

Causes range from mild (a change in food, mild nausea, stress, hot weather) to significant (dental pain, infection, organ disease, or the side effects of another illness). A dog recovering from surgery or on other medication may also lose interest in food. [1]

When it's worth a vet visit

See a vet if your dog hasn't eaten for more than 24 hours, is losing weight, or is off food alongside vomiting, lethargy, or other signs. In older or already-ill dogs, don't wait as long.

How vets help appetite

Beyond treating the underlying cause, a veterinarian may prescribe an appetite stimulant such as capromorelin (Entyce) to help a dog eat while it recovers. Whether it's appropriate, and at what dose, is a veterinary decision — we never set doses.

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Frequently asked questions about dog not eating

How long can a dog go without eating?

A healthy adult dog can miss a meal or two without harm, but going beyond about 24-48 hours, especially with other signs, warrants a vet. Puppies and sick dogs need attention sooner.

Can I give my dog an appetite stimulant?

Appetite stimulants like Entyce are prescription medications. A vet decides whether one is appropriate and sets the dose.

Veterinary review. This guide was reviewed for clinical accuracy by Dr. Olivier Toulza. Guidance is clinician-governed; we never state a dose.

Related digestive & nausea guides

Dog Nausea · Dog Vomiting · Dog Vomiting And Diarrhea · Dog Throwing Up Blood · Dog Throwing Up White Foam · Dog Throwing Up Yellow

Sources & References

  1. Merck Veterinary Manual — Anorexia in animals