What are the common possible causes of chronic gastritis?

Chronic gastritis may result from dietary intolerance, prolonged irritation, parasites, or immune-mediated reactions, among other causes. The exact cause requires veterinary investigation — including bloodwork, imaging, endoscopy, and biopsy — and further testing should follow your vet's guidance.

When is endoscopy or biopsy needed?

If symptoms recur or fail to improve with medication and dietary adjustments, your vet may recommend endoscopy with sampling to confirm mucosal changes or rule out other conditions. The decision to proceed is made jointly by your vet and you.

How can I adjust my pet's diet at home to help ease symptoms?

Under your vet's guidance, a low-irritant or prescription diet trial may help. Avoid sudden food changes or excessive treats. Always consult your vet before making dietary adjustments to avoid delaying appropriate treatment.

What is the prognosis for chronic gastritis and how likely is it to recur?

Chronic gastritis is a condition that requires long-term management. When the underlying cause is identified and controlled, symptoms can improve significantly; however, recurrence is possible. Regular check-ups and ongoing monitoring of weight and appetite are recommended.

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

Chronic Gastritis in Dogs & Cats: Symptoms, Endoscopy & Treatment Guide [2025]

Chronic gastritis is persistent inflammation of the gastric mucosa that causes vomiting and loss of appetite. Diagnosis requires endoscopy with biopsy. Treatment includes dietary modification, antacids, and immunosuppressive therapy.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ACVIM, WSAVA, Taiwan Veterinary Internal Medicine Society

When to See a Vet

Seek immediate veterinary care (emergency)

•Persistent vomiting or refusal to eat for 24 hours
•Vomiting or stool contains bright red blood or black material
•Obvious dehydration or extreme lethargy with poor responsiveness

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

•Appetite continues to decline for more than 48 hours
•Intermittent retching or frequent repeated vomiting
•Ongoing weight loss or reduced activity

01What symptoms indicate something is wrong?

Chronic gastritis commonly causes recurring or ongoing gastrointestinal discomfort. Watch for persistent changes in appetite, vomiting, and bowel habits, and monitor weight and energy levels to help catch problems early.

Decreased appetite or refusal to eat, lasting several days or more
Repeated vomiting or frequent retching
Intermittent diarrhoea or changes in stool character (colour, consistency, or blood in stool)
Progressive weight loss — regular weigh-ins are recommended
Notable increase or decrease in water intake
Decreased energy, reduced activity, or loss of interest in usual activities

Seek emergency care immediately if you notice the following symptoms:

⚠️ Unable to eat or vomiting continuously for more than 24 hours
⚠️ Fresh red or black blood in vomit or stool
⚠️ Signs of significant dehydration, dry mouth, or extreme lethargy or unresponsiveness

02How to assess abnormalities at home: key observations and emergency warning signs

Keeping detailed records at home helps your vet quickly understand the progression and likely cause. Try to note timing, frequency, and any accompanying signs as accurately as possible.

Record when symptoms started and note specific times of change
Weigh your pet on the same scale daily and log any changes
Photograph vomit or faeces for your vet's reference
Log the frequency and timing of vomiting, and whether it contains blood or yellow bile
Track and record daily water intake and any changes in drinking frequency
Observe changes in alertness, activity level, and interest in food

03How will the vet diagnose this condition? Common diagnostic tests

At the clinic your vet will begin with laboratory tests and imaging, and may proceed to endoscopy or tissue sampling if needed, combining all findings to identify the likely cause.

Blood biochemistry panel

assesses liver and kidney function and electrolyte balance

Urinalysis

rules out metabolic or renal conditions

Abdominal X-ray

checks for obstruction, masses, or other abnormal findings

Abdominal ultrasound or CT scan

provides more detailed imaging information

Endoscopy (gastroscopy)

direct visualisation of the gastric mucosa with the option to collect samples

Tissue biopsy

confirms chronic inflammation or other pathological changes

04How is chronic gastritis treated and managed? Medication, dietary changes, and home care

Management of chronic gastritis focuses on supportive care, dietary adjustment, and addressing the underlying cause, combined with regular monitoring to assess treatment response and long-term control.

Short-term anti-nausea medication and supportive care as assessed by your vet
Transition to a low-irritant or prescription diet, adjusted gradually based on response
Continuously monitor weight and symptoms, and bring records to follow-up appointments
Schedule follow-up visits as directed to recheck bloodwork or imaging
Referral for endoscopy, advanced diagnostics, or specialist evaluation if required
Regular recheck appointments are recommended to confirm long-term disease control and assess prognosis

05What to prepare before your vet visit: key information to help your vet diagnose quickly

List the onset of each symptom and details of how they have changed day by day

Gather and bring photos or videos of any vomit or faeces

Note the current food brand, ingredients, and any recent dietary additions

Bring recent weight records or weigh-in data

List all current medications, supplements, and dosing records

Bring any previous test reports for comparison

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.