Loss of Appetite in Pets: Reasons, Home Diagnosis and Home Remedies (Evidence-Based Guide)

Quick Answer (Key Takeaways)

What is loss of appetite in pets? Veterinarians call it anorexia (no eating) or hyporexia (eating less than normal). It is a symptom, not a disease, and it can accompany almost any illness, from a dental abscess to kidney disease, infection, pain or cancer.

• Cats are higher risk than dogs. A cat that eats little or nothing for roughly three to four days can develop hepatic lipidosis (fatty liver disease), which is life-threatening, so a cat that is not eating is treated as urgent.
• Dogs tolerate short fasts better, but a dog that skips more than a meal or two, or refuses food with vomiting, diarrhea or lethargy, needs veterinary advice promptly.
• Home checks can sort urgent from mild (gum colour, hydration, mouth, temperature, water intake), but they do not replace diagnosis.
• Safe home remedies (gently warming food, adding dog-safe low-sodium broth, switching texture) can help mild, short-lived cases. Never use onion, garlic or seasoned human broths.
• Prescription appetite stimulants exist (for example mirtazapine and capromorelin) and are used only under veterinary direction.

What Is Loss of Appetite in Pets? (Definitions That Matter)

Veterinary references divide reduced eating into three patterns: hyporexia (reduced intake), anorexia (no intake) and dysrexia (abnormal or picky eating pattern). Recurrent episodes are usually a sign of an underlying problem rather than fussiness.

One distinction is especially useful at home. VCA Animal Hospitals' dog guidance separates true anorexia, where the animal is simply not interested in food, from pseudo-anorexia, where the pet wants to eat but cannot because of difficulty picking up, chewing or swallowing food. A dog with a painful tooth and a dog with kidney disease may both leave the bowl full, but the workup and treatment are completely different. Working out which one you are dealing with is the first step a veterinarian takes.

Why Does a Pet Stop Eating? Main Causes

A small-animal internal medicine textbook excerpt on weight loss and anorexia groups the causes into broad categories: psychological factors (especially in cats), inability to smell food, painful swallowing, inflammation, infection, immune-mediated disease, cancer, tissue necrosis, drugs, and gastrointestinal or abdominal disease that causes nausea or pain. In practical terms, these look like the following.

1. Mouth and dental pain

Tooth decay, gum disease, abscesses and oral lesions make chewing painful. Pets with mouth pain often show drooling, pawing at the face, dropping food, or approaching the bowl eagerly and then walking away. This is a classic example of pseudo-anorexia.

2. Nausea and gastrointestinal disease

Gastroenteritis, pancreatitis, inflammatory bowel disease, foreign bodies and constipation all suppress appetite. Appetite loss with vomiting, diarrhea or belly pain is more concerning than appetite loss alone.

3. Systemic and organ disease

Kidney disease, liver disease, diabetes, hyperthyroidism (cats), heart disease and cancer commonly present first as gradual appetite decline, particularly in senior pets. VCA's guidance on feline hepatic lipidosis notes that in more than 90% of affected cats an underlying illness (such as inflammatory bowel disease, other liver disease, cancer, pancreatitis, anxiety, respiratory disease or diabetes) triggered the inappetence in the first place.

4. Infections and fever

Viral and bacterial infections reduce appetite. In cats, upper respiratory infections (for example feline calicivirus or herpesvirus) block the sense of smell, and smell is a major driver of feline appetite. A small Costa Rican clinic report of 45 anorexic dogs and cats found that 46% had an infectious disease and 26% died, highlighting that appetite loss can signal serious illness, although the sample is small and from a single practice.

5. Pain

Osteoarthritis, injury or surgery pain lowers food intake. Cats, being both predator and prey, hide pain well, so a reduced appetite and more sleeping may be the only visible signs.

For related reading on everyday comfort, see our orthopedic dog bed guide. Bedding does not treat the cause of appetite loss or replace veterinary pain management.

6. Medications, vaccines and treatments

Drug side effects are a recognised cause of reduced appetite, and chemotherapy is a well-documented one. Published figures compiled in Today's Veterinary Practice report inappetence in roughly 17% to 51% of dogs depending on the chemotherapy drug (for example about 19% with epirubicin and 36% with cyclophosphamide in the studies cited).

7. Stress, environment and behavior

Moving house, a new pet, travel, loud noise, a changed routine or a new food can all suppress eating, especially in cats. High environmental temperature is also listed among dog appetite suppressors, so hot weather is worth considering.

For more seasonal care tips, read how weather changes affect your pet’s health.

8. Toxins and dietary indiscretion

Ingesting a toxic plant, human food or chemical can cause sudden appetite loss, often with vomiting. If poisoning is possible, call a veterinarian or poison helpline immediately instead of waiting.

9. Food-related causes

A stale, spoiled or newly changed diet, or a fussy habit reinforced by constant treats, can reduce appetite. This is usually the least worrying cause, but it should be diagnosed only after medical causes are considered unlikely.

How Long Is Too Long? Red-Flag Timelines

Situation	General guidance
Cat eating nothing or very little	Contact a vet within 24 hours. Hepatic lipidosis typically follows about 3 to 4 days of anorexia, and overweight cats are at greatest risk.
Healthy adult dog, otherwise bright, still drinking	A single skipped meal is usually not an emergency, but call your vet if it continues beyond about 24 hours.
Dog not eating with vomiting and/or diarrhea	The American Kennel Club advises contacting a vet within 8 to 12 hours.
Puppies, kittens, seniors, diabetics, pets on medication, or very small breeds	Call the same day. They have fewer reserves.
Yellow gums, eyes or skin (jaundice)	Urgent veterinary care.
Collapse, repeated vomiting, bloated painful abdomen, pale gums, difficulty breathing, suspected toxin	Emergency.

These thresholds are general rules of thumb drawn from veterinary client resources; your vet may advise earlier action based on your pet's age and health.

Why Cats Are a Special Risk: Hepatic Lipidosis

Hepatic lipidosis, also called fatty liver syndrome, is one of the most common liver diseases in cats. When a cat stops eating, the body mobilises fat rapidly, and the liver becomes overwhelmed, trapping fat inside liver cells and impairing its function. Key facts from VCA Animal Hospitals and veterinary teaching resources:

• It usually follows around three to four consecutive days of anorexia, and risk is higher if the cat was overweight or obese beforehand.
• Affected cats often become jaundiced (yellow tinge to eyes, gums or skin).
• Diagnosis relies on blood tests, ultrasound and sometimes a liver sample.
• The cornerstone of treatment is aggressive nutritional support, often through a feeding tube, plus intravenous fluids, anti-nausea medication, and treating the original disease.
• Average tube-feeding time before cats eat voluntarily again is reported at roughly six to seven weeks by VCA, while a vet teaching resource describes one to two weeks of assisted feeding for many cats, so duration varies widely.
• Veterinary clinic resources report survival approaching 90% when nutritional support starts promptly, which is why waiting "to see if it passes" in a cat is a risky strategy.
• Re-feeding must be gradual, often starting with half or less of the calorie target, because sudden feeding can shift potassium and other electrolytes and cause "refeeding" complications. This is another reason a vet should supervise.

Home Diagnosis: A Step-by-Step Checklist (Before You Call the Vet)

You cannot diagnose the cause at home, but you can gather information that makes your vet's job faster and may reveal an emergency. Always keep yourself safe; if your pet is painful, a muzzle or towel may be needed, and a reluctant pet should not be forced.

Step 1: Define the problem. Is your pet eating nothing, eating less, or eating only certain foods? Does it approach the bowl and then back away (suggesting pain or nausea) or ignore it completely?

Step 2: Check the timeline. Write down the last time your pet ate a full meal, any new foods or treats, recent medications, vaccines or travel, and possible exposure to plants, chemicals or garbage.

Step 3: Look in the mouth. Gently lift the lips. Look for red or swollen gums, broken or loose teeth, bad breath, lumps, ulcers or something stuck. Do not poke around if your pet resists.

Step 4: Check gum colour and capillary refill. Healthy gums are generally pink and moist. Pale, white, blue or yellow gums are warning signs. Press a gum with a fingertip until it blanches; colour should return in about one to two seconds.

Step 5: Assess hydration. Gently lift the skin over the shoulders; it should snap back promptly. Tacky gums and slow skin return suggest dehydration. (Skin tenting is less reliable in thin, elderly or very overweight pets.)

Step 6: Monitor water intake and elimination. Note whether your pet is drinking more or less than usual, urinating more or less, vomiting, or having abnormal stools. Increased thirst and urination with poor appetite can point to kidney disease or diabetes.

Step 7: Take the temperature, if you can do so safely. A normal range for dogs and cats is commonly given as about 100.5°F to 102.5°F (38.1°C to 39.2°C). A reading outside that range with poor appetite warrants a call to your vet.

Step 8: Observe behavior and body. Look for lethargy, hiding, restlessness, panting, a hunched posture, belly tenderness, limping, or coughing and nasal discharge. Eating less and sleeping more together should be reported to a veterinarian.

Step 9: Weigh your pet and compare with previous weights. Unexplained weight loss, together with decreased appetite, deserves a prompt exam.

Step 10: Keep a short log. Record meals, treats, vomiting episodes, stools, water intake and photos of anything unusual. Bring any packaging of suspected toxins.

What your veterinarian will usually do next

Expect a detailed history and full physical exam, then targeted tests depending on findings: bloodwork and a complete blood count, urinalysis, imaging (X-rays or ultrasound), and sometimes endoscopy or biopsies. The Costa Rican case series noted that a complete blood count was the most useful first lab test, and that quick diagnosis allows treatment to start in time. When no diagnosis is evident, a vet may run a therapeutic trial.

Home Remedies and Supportive Care: What Is Reasonable (and What Is Not)

Home measures are supportive. They are suitable only for pets that are bright, alert, drinking, and have been off food for a short time with no red flags. They are not a cure for the underlying cause.

Evidence-informed tips that are generally considered safe

1. Gently warm the food. A few seconds in the microwave (stir and check temperature to avoid hot spots) or a splash of warm water releases aroma, which matters for pets with weak or blocked smell, including seniors and cats with congestion.
2. Add a little moisture. Warm water or dog-safe, low-sodium broth over kibble can soften texture and raise palatability. The AKC lists warm broth, warm water and swapping dry for wet (or the reverse) as options.
3. Choose the right broth. Many shop-bought human broths and gravies contain onion or garlic powder, which are toxic to dogs and cats. Use a pet-specific broth or plain homemade broth with no onion, garlic or seasoning, and keep portions small (a spoonful or two).
4. Offer bland, simple food if the stomach is upset. Plain boiled chicken with rice or plain pumpkin is commonly used for dogs with mild digestive upset, but only for a short period and only if your vet agrees. For plain meat baby food, read the label; some varieties contain onion or garlic powder.
5. Offer small, frequent meals, hand-feed, and sit quietly with your pet. Calm company helps stressed animals.
6. Reduce stress. Keep routines, litter boxes, and feeding spots stable, place food away from other pets, and provide quiet, comfortable space.
7. Encourage drinking. Fresh water, a pet fountain or ice cubes of dog-safe broth can help hydration.

If you are updating your dog's everyday feeding setup, explore our Mint Green Deep Stainless Steel Dog Bowl. A feeding bowl is an everyday accessory, not a treatment for appetite loss.

What to avoid

• Do not wait several days with a cat. Do not try to "starve a cat into eating."
• Do not force-feed without veterinary guidance. Food aversion is a real phenomenon, and forced feeding can worsen it or cause aspiration.
• Do not give human appetite stimulants, supplements, or medication. Doses for pets differ greatly, and some human products are toxic.
• Avoid onions, garlic, chives, leeks, grapes, raisins, macadamia nuts, chocolate and xylitol-sweetened products.
• Avoid constant treat swapping, which can train a pet to hold out for something tastier.

Prescription appetite stimulants: what the evidence says

If home measures are not enough, your veterinarian may consider an appetite-stimulating drug while the underlying cause is investigated. These are not do-it-yourself options.

• Mirtazapine has an established role in cats, including a transdermal ointment product approved for cats. A Today's Veterinary Practice review notes it appears more reliable in cats than in dogs, and that it has been shown to improve appetite and weight in cats in a placebo-controlled study. Dosing intervals differ with disease: for cats with chronic kidney disease, a less frequent schedule has been recommended because the drug clears more slowly.
• In dogs, evidence is growing. A 2025 study (retrospective review of 107 dogs plus a 25-dog double-blind crossover trial) reported that appetite improved in 68.6% of mirtazapine-treated dogs versus 37.5% of untreated controls, and that all 14 dogs given mirtazapine on day one accepted food versus 7 of 11 on placebo. The authors concluded it may be a safe second-line option when feeding by tube is not feasible, though they acknowledged limitations, including small size and high exclusion rates.
• Capromorelin is a ghrelin-receptor agonist (it mimics the hunger hormone). It was approved by the US FDA in May 2016 for dogs (Entyce) and later for cats (Elura). In the pivotal dog study, owners reported increased appetite in about 68.6% of treated dogs versus about 44.6% on placebo, and 76% of treated dogs gained weight. Veterinary pharmacology reviews advise caution in critically ill cats, in those with possible heart disease, and note effects on blood glucose.
• Other options include cyproheptadine, corticosteroids and anti-nausea drugs such as maropitant, chosen according to the diagnosis. Veterinary pharmacology reviews note that data for some of these in dogs and cats is limited.

Whenever a pet is not eating because it is nauseated, in pain or dehydrated, those problems must be treated too. An appetite stimulant alone does not fix the root cause.

When Appetite Loss Is an Emergency

Go to a vet or emergency clinic right away if your pet shows any of the following alongside poor appetite:

• Yellow gums, eyes or skin
• Persistent or bloody vomiting, or bloody stool
• Swollen, painful abdomen or unproductive retching (especially in deep-chested dogs)
• Extreme lethargy, weakness, or collapse
• Difficulty breathing
• Suspected poisoning (call your vet or a poison helpline immediately)
• No urination for 24 hours, or straining (especially male cats)
• Cat refusing food for 24 hours or more, or any pet with known diabetes or kidney disease that stops eating

Prevention: Keeping Appetite Healthy

• Annual or twice-yearly checkups, with dental exams, particularly for seniors.
• Weight management. Overweight cats are most vulnerable to hepatic lipidosis if they ever stop eating.
• Introduce diet changes gradually over about a week.
• Maintain routines and stable feeding stations; reduce household stress.
• Store food correctly and discard stale food.
• Track appetite and weight, because small changes often come first.
• Keep toxins out of reach, including human foods that are harmful to pets.

Frequently Asked Questions (FAQ)

How long can a dog go without eating?

A healthy adult dog that is otherwise bright and drinking water can usually tolerate about a day without food, but you should call your veterinarian if it continues beyond 24 hours, or sooner if there is vomiting, diarrhea, lethargy or pain. Puppies, seniors and dogs with medical conditions should be seen sooner.

How long can a cat go without eating?

Less than a dog. A cat that eats little or nothing for 24 to 48 hours should be assessed, and around three to four days of anorexia can trigger hepatic lipidosis, particularly in overweight cats. Treat a cat not eating as urgent.

Why is my dog not eating but acting normal?

Mild causes include a diet change, heat, stress, stale food, recent vaccination or too many treats. Early dental pain or nausea can also be subtle. If the behavior persists beyond one to two meals, or if your dog's weight, thirst or stool changes, see your vet.

Why is my cat not eating but drinking water?

Drinking shows she is not completely off, but it does not make appetite loss safe. Causes include dental pain, nausea, nasal congestion that blocks smell, kidney disease or stress. Contact your veterinarian within a day.

Can I give my pet human appetite stimulants or supplements?

No. Pet doses and safety differ from human ones, and several human products or ingredients (such as xylitol or onion/garlic) are dangerous. Only use appetite stimulants prescribed by a vet.

Is bone broth safe for sick pets?

Plain, low-sodium, onion-free and garlic-free broth in small amounts is widely used to entice sick dogs and cats and add moisture. Many commercial human broths include onion or garlic powder, so check labels or choose a pet-specific product. Broth is not a complete diet and does not replace veterinary care.

What are the best appetite stimulants for dogs and cats?

There is no single best option. Mirtazapine has the longest track record in cats; capromorelin is FDA-approved for appetite stimulation in dogs and cats; and the choice depends on the diagnosis, other conditions and other medications. Your veterinarian decides.

Should I force-feed my pet with a syringe?

Only if your veterinarian has shown you how and advised it. Improper force-feeding risks aspiration (food entering the lungs) and food aversion. If a pet needs assisted feeding, a feeding tube is often a safer, less stressful and more accurate option.

Is loss of appetite normal in older pets?

Some decline in smell and taste occurs with age, but a clear drop in eating is not "just old age." Dental disease, kidney disease, hyperthyroidism (cats), arthritis pain and cancer are common treatable causes.

Can stress alone cause a pet to stop eating?

Yes, especially cats. Moves, new pets, boarding or loud noise can suppress appetite, but stress should be diagnosed only after medical causes are ruled out, and a cat should not be left without food for more than a day or two.

When should I take my pet to the vet for not eating?

Same day for puppies, kittens, seniors, diabetic pets, cats and any pet with vomiting, diarrhea, lethargy, pain, jaundice or breathing problems. Otherwise, within 24 hours if there is no improvement.

Conclusion

Loss of appetite in pets is a common sign with a very wide range of causes, from a sore tooth or a stressful move to kidney disease, infection, pain or cancer. The evidence is clear on three points. First, cats can become seriously ill within days of not eating. Second, a short home check of the mouth, gums, hydration, temperature and behavior helps you describe the problem and spot emergencies. Third, simple home measures such as warming food, adding pet-safe broth and reducing stress can support mild cases, while prescription appetite stimulants and assisted feeding belong in veterinary hands. When in doubt, call your veterinarian early.

Medical disclaimer: This article provides general information and is not veterinary advice. Always consult a licensed veterinarian about your pet's specific situation.

References and Further Reading

The sources below were consulted for this article. Statistics are paraphrased from them.

1. VCA Animal Hospitals. Anorexia in Dogs (T. Hunter, R. Llera, R. Downing). vcahospitals.com/know-your-pet/anorexia-in-dogs
2. VCA Animal Hospitals. Hepatic Lipidosis in Cats (Fatty Liver Syndrome in Cats). vcahospitals.com/know-your-pet/fatty-liver-syndrome-in-cats and /liver-disease-fatty-liver-syndrome-in-cats (last updated 2023).
3. Clark M. Drugs Used for Appetite Stimulation in Dogs & Cats. Clinician's Brief, December 2022. cliniciansbrief.com/article/veterinary-drugs-appetite-stimulation-dogs-cats
4. The Evolving Clinical Management of Chronic Inappetence. Today's Veterinary Practice, March/April 2023. todaysveterinarypractice.com (Chronic Inappetence, TVP 2023-0304).
5. Johannes CM. The Use of Capromorelin for the Clinical Problem of Inappetence. Today's Veterinary Practice. todaysveterinarypractice.com/pharmacology/the-use-of-capromorelin-for-the-clinical-problem-of-inappetence/
6. Evaluation of the Short-Term Effects of Mirtazapine on Appetite Stimulants in Dogs: A Retrospective Study and a Placebo-Controlled Trial. PubMed Central (PMC12427372), 2025; summarized by RCVS Knowledge. ncbi.nlm.nih.gov/pmc/articles/PMC12427372
7. WSAVA Global Nutrition Committee. Feeding Guide for Hospitalized Dogs and Cats (2013). wsava.org
8. Fallas Valencia PG. Principales diagnósticos asociados al signo de anorexia en la Clínica Veterinaria Gómez. Universidad Nacional, Costa Rica, 2009. repositorio.una.ac.cr/handle/11056/12996
9. Vetster. Lack, Loss, or Reduced Appetite (Dysrexia, Anorexia, and Hyporexia) in Cats (editorial references include Today's Veterinary Practice, Cornell University College of Veterinary Medicine and Veterinary Partner). vetster.com
10. Small-animal internal medicine textbook excerpt, Weight Loss or Anorexia of Unknown Cause (Tables 9-11 and 9-12), via Vetology. platform.v2.vetology.net
11. Outters G. Anorexia in the cat constitutes an emergency. La Semaine Vétérinaire, no. 1434, 21 January 2011, pp. 34-35 (summarized by Darwin Nutrition).
12. VetPrep. Nutritional Support in Hepatic Lipidosis: Case Study for Vet Students (citing K. Smith, Veterinary Practice, 2018, and L. Cornejo, dvm360, 2011).
13. Mar Vista Animal Medical Center. Hepatic Lipidosis client handout. marvistavet.com/hepatic-lipidosis.pml
14. American Kennel Club. Why Won't My Dog Eat? akc.org/expert-advice/health/why-wont-my-dog-eat