What might cause a dog or cat to suddenly stop eating?

Loss of appetite in dogs and cats can be caused by oral pain, gastroenteritis, internal organ disease, or stress. A vet will take a history and run appropriate tests to identify the cause and guide treatment.

How should owners monitor and record changes at home?

Weigh your pet at the same time each day, log food intake and food type, and record short videos of eating behaviour or vomiting episodes to share with your vet.

How long should I wait before seeing a vet?

If your pet continues to refuse food for more than 24–48 hours, or if vomiting, lethargy, or other symptoms are present, seek veterinary advice promptly. Severe cases require emergency care immediately.

What tests might be done at the clinic?

Common investigations include a physical examination, blood and biochemistry tests, abdominal ultrasound, and X-rays. Endoscopy or further imaging may be arranged if the vet considers it necessary.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Anorexia in Dogs & Cats: Symptoms, Diagnosis & Home Care [2025]

Anorexia is a symptom, not a disease itself — finding the underlying cause, such as infection, pain, gastrointestinal problems, or metabolic disease, is essential.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: WSAVA, ISFM, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

•Completely refuses food for two consecutive days and is not drinking water
•Frequent vomiting with severe lethargy and little or no response
•Persistent obvious abdominal pain or marked abdominal swelling

Schedule a clinic visit as soon as possible (within 24-72 hours)

•Food intake has continued to decrease for more than two days
•Gradual weight loss with a clear decrease in activity level
•Vomiting or diarrhea occurs together with reduced appetite

01What symptoms indicate something is wrong?

Anorexia in dogs and cats typically presents as a noticeable reduction in food intake, and may be accompanied by weight loss, changes in energy levels, or gastrointestinal discomfort. Watch for concurrent vomiting, diarrhoea, or signs of pain.

Noticeably reduced food intake or complete refusal to eat for more than one day
Ongoing weight loss over more than two weeks, or significant weight loss in a short period
Visible signs of pain when the abdomen is touched or during movement
Lethargy, markedly reduced activity, or reluctance to interact
Vomiting or diarrhoea occurring alongside loss of appetite
Changes in water intake, altered bowel habits, or abnormal stool consistency

Seek emergency care immediately if you notice the following symptoms:

⚠️ Complete refusal to eat for more than 48 hours combined with weakness or lethargy
⚠️ Persistent vomiting or diarrhoea with signs of dehydration
⚠️ Obvious abdominal bloating or severe pain response on contact

02How to assess the situation at home: monitoring tips and when to seek emergency care

Observing and recording specific changes at home helps your vet quickly understand the progression and likely causes. Weigh your pet and track food intake at the same time each day.

Weigh your pet at the same time each day and keep a detailed record of the trend
Log daily food intake, food type, and any instances of refusal
Record short videos of eating behaviour or refusal for the vet to review
Monitor and record bowel movement frequency, stool consistency, and colour
Note when symptoms began and whether any new food, treats, or medications were introduced
Compile your records and book a vet appointment promptly to aid the assessment

03How will the vet diagnose the problem? Common examination steps

At the clinic, the vet will work through a range of basic to advanced assessments to rule out common gastrointestinal or systemic causes, and may arrange imaging or endoscopy when further evaluation is needed.

Physical examination

including cardiac and lung auscultation, abdominal palpation, and body condition assessment

Blood and biochemistry tests

to evaluate liver and kidney function and detect electrolyte imbalances

Abdominal ultrasound

to assess organ structure, detect masses, or identify fluid accumulation

X-rays

to examine gastrointestinal positioning, identify foreign bodies, or detect changes in organ size

Endoscopy

allows direct visualisation of the gastrointestinal mucosa, and enables tissue sampling or foreign body retrieval

04What treatment and care are needed after diagnosis? Medications, diet changes, and home management

Treatment varies depending on the underlying cause. Common approaches include managing vomiting, adjusting the diet, and providing supportive care, with follow-up appointments and tests to monitor recovery.

Symptom management: anti-nausea medication or supportive fluid therapy to stabilise the condition
Dietary adjustment: small frequent meals or a highly digestible prescription diet
Home monitoring: track weight, appetite, and elimination patterns and continue keeping records
Follow your vet's schedule for check-ups and any necessary blood tests or imaging follow-up
If symptoms do not improve, your vet may recommend a referral to a gastrointestinal specialist

05What to prepare before the vet visit: key information to help identify the cause quickly

Bring a log of when symptoms started and how they have changed each day

Share videos or photos of eating behaviour and bowel movements for reference

List all current medications, supplements, and their dosages

Bring any previous blood test results or imaging reports if available

At the appointment, ask the vet whether a specialist referral is warranted

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

Related Symptoms (You May Also Be Looking For)

Halitosis

Bad breath

Drooling

Saliva dripping

Weight Loss

Decreased body weight