What are the common causes of gastric and duodenal ulcers?

Common causes of ulcers in dogs and cats include medication irritation, such as long-term use of anti-inflammatory drugs, stress from severe illness, infection, or foreign material in the stomach. The exact cause should be confirmed by your vet through examination and diagnostic testing.

Does every vomiting case need an endoscopy?

Not always. Brief vomiting may first be monitored with basic testing. If vomiting is repeated, accompanied by blood, or blood tests are abnormal, endoscopy can help by allowing direct inspection and biopsy. Your vet will decide based on the assessment.

How long does it take for gastrointestinal bleeding to show symptoms?

Depending on the amount and speed of bleeding, signs may appear within hours to days. They can include vomiting blood, black tarry stools, weakness, or poor appetite. If bleeding is suspected, seek veterinary care promptly.

What follow-up checks are usually needed?

Follow-up visits often include a clinical examination, blood tests to monitor haemoglobin and electrolytes, weight records, and repeat imaging or endoscopy if needed. The follow-up schedule depends on the illness and response to treatment.

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

Gastric and Duodenal Ulcers in Dogs and Cats: Vomiting, Blood in Vomit, Endoscopy & Care [2025]

Gastric and duodenal ulcers may be caused by medication, tumours, or severe stress from illness. Signs include vomiting, black stools, and anaemia. Endoscopy may be needed for diagnosis, and treatment includes acid-suppressing medication and managing the underlying cause.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

PetHealthMap Editorial Team

Sources: ACVIM, AVMA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Vomiting fresh blood or coffee-ground-like material
•Black, tarry, or abnormally sticky stools
•Collapse, confusion, or unresponsiveness

Schedule a Clinic Visit Soon (within 24–72 hours)

•Repeated vomiting but still able to drink water or eat small amounts
•Noticeably reduced appetite or complete refusal to eat
•Signs of discomfort or reluctance to be touched when abdomen is palpated

01What symptoms suggest something is wrong?

When a dog or cat has a gastric or duodenal ulcer or mucosal erosion, digestive signs and whole-body changes are common; some cases are emergencies and need immediate care.

Low energy, a clear drop in activity, or unusual sleepiness
Repeated vomiting, which may contain blood or look like coffee grounds
Reduced appetite or complete refusal to eat, with a noticeable drop in food intake
Rapid weight loss or signs of weakness and fatigue
A faster heart rate or rapid breathing should be treated as a warning sign
Obvious pain or discomfort when the abdomen is touched or when eating

Seek emergency care immediately if you notice the following symptoms:

⚠️ Vomiting fresh blood or material that looks like coffee grounds
⚠️ Black, tarry, or unusually sticky stools
⚠️ Collapse, confusion, or unresponsiveness
⚠️ Pale or bluish gums, suggesting anaemia or poor circulation

02How can you assess the problem at home? Key observations and emergency criteria

Information you record and prepare at home before the visit can help your vet assess the situation faster and plan the next tests or treatment steps.

Record when changes in mood and activity level started and how they progressed
Count the number of vomiting episodes and take photos of the vomit for your vet to review
Record changes in appetite, whether your pet is refusing food completely, and recent drinking habits
Take photos of stools and keep a small stool sample for testing if possible
Describe any weight changes, including recent weigh-in results and dates
Avoid pressing on the abdomen, as this may cause more pain or worsen the condition
If signs persist or worsen, arrange specialist or emergency veterinary care as soon as possible

03How will the vet diagnose it? Common tests

At the clinic, your vet will combine a physical examination with imaging and laboratory tests to confirm whether there is an ulcer, bleeding, or other complications, then decide on the treatment plan.

Physical examination

heart and lung auscultation, abdominal palpation, and overall health assessment

Blood tests

complete blood count, electrolytes, and liver and kidney function markers

X-rays

to rule out gastric perforation, tumours, or other abdominal abnormalities

Endoscopy

direct examination of the stomach and duodenal lining, with biopsy if needed

Histopathology (biopsy)

laboratory examination of tissue samples to confirm the nature of the lesion

Advanced imaging (CT)

further assessment for complex cases or suspected perforation

If endoscopy is needed, choose a specialist hospital with endoscopy equipment and relevant experience

04What treatment and care are needed after diagnosis? Medication, diet adjustment, and care guidance

Treatment usually focuses on supportive care and protecting the stomach and intestinal lining. Severe cases may need blood transfusion or hospitalisation, and follow-up visits plus home records are important for recovery.

Medication support: anti-vomiting treatment, acid suppression, mucosal protectants, and other supportive care
Blood transfusion or fluid therapy: hospital care may be needed for severe anaemia or dehydration
Diet adjustment: short-term use of an easily digestible prescription diet or bland food in small, frequent meals
Regular rechecks to monitor blood values, body weight, and improvement in clinical signs
Home care: continue recording vomiting episodes, appetite, and activity level
If signs recur or do not improve, a specialist recheck or further testing is recommended

05What should you prepare before seeing the vet? Key details that help identify the cause

Take and bring photos of vomit and stools for your vet to review

Record when the illness began, the first abnormal sign, and a timeline of how symptoms changed

List recent foods, treats, and any possible history of foreign object exposure

Bring recent blood test or imaging reports, if available, for comparison

Prepare a list of current medications or supplements, including doses

Use a secure carrier and contact a clinic with endoscopy capability in advance

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.