What are the common causes of small intestinal dysbiosis?

Common causes include dietary changes, intestinal infections, parasites, or prolonged use of certain medications. A thorough history combined with diagnostic tests can help identify the likely cause — speak with your vet for advice specific to your pet.

What tests are needed to confirm dysbiosis?

Common tests include blood work, faecal microscopy and pathogen screening (such as PCR), abdominal ultrasound, and endoscopic biopsy. The specific combination of tests will depend on your pet's situation — follow your vet's recommendations.

Can I give my pet probiotics to help restore the gut microbiome?

Probiotics may be helpful, but their effectiveness varies between individuals and products. It is best to discuss this with your vet before starting, and to use the product and dosing they recommend.

How long will it take for symptoms to improve?

Mild cases may improve within a few days to a week. Chronic conditions or those requiring treatment adjustments may take weeks to months to resolve. Regular follow-up visits and repeat tests as directed by your vet are important.

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

Small Intestinal Dysbiosis in Dogs & Cats: Symptoms, Diagnosis & Dietary Treatment [2025]

A guide to small intestinal dysbiosis — vomiting, diarrhoea, and gut microbiome imbalance in pets

Take 1 minute to check the symptoms first

Last updated: 2025/12/16

Pethealthmap editorial team

Sources: ACVIM, WSAVA, Taiwan Academy of Veterinary Internal Medicine

When to See a Vet

Immediate veterinary care required (emergency)

•Persistent, large-volume vomiting with a complete inability to eat
•Fresh blood in the stool or a large amount of black stool
•Obvious dehydration with markedly reduced skin elasticity

Schedule a veterinary appointment as soon as possible (within 24-72 hours)

•Intermittent vomiting, but still able to drink water and eat
•Repeated diarrhea or soft stool with mucus
•Reduced appetite with weight loss over a short period

01What symptoms indicate something is wrong?

Small intestinal dysbiosis typically presents as non-specific digestive problems. Symptoms may come and go or persist over time — assess severity by observing the overall pattern.

Intermittent or persistent vomiting, which may contain food or stomach fluid
Frequent diarrhoea or soft stools, sometimes with mucus or changes in stool consistency
Unexplained, gradual weight loss
Changes in appetite (reduced appetite or refusal to eat) and decreased energy levels
Tenderness or discomfort when the abdomen is touched

Seek emergency care immediately if you notice the following symptoms:

⚠️ Persistent, forceful vomiting with inability to keep food down
⚠️ Presence of fresh blood or large amounts of dark, tarry stools
⚠️ Obvious dehydration with noticeably reduced skin elasticity

02How to assess the situation at home — what to watch for and when to go to the emergency clinic

Observing and recording key information at home helps your vet quickly understand the timeline and likely causes.

Record the number of vomiting episodes, when they occur, and what the vomit looks like
Take photos or video of vomiting and stools as a reference
Keep a daily log of stool consistency, colour, and frequency
Weigh your pet weekly and track any weight changes
Monitor for changes in alertness, activity level, and water intake
If symptoms persist, arrange a gastrointestinal specialist evaluation as soon as possible

03How will the vet make a diagnosis? Common diagnostic tests

Your vet will combine the history and test results to identify the likely cause and determine which further tests are needed.

Full physical examination

assess hydration status, body temperature, and abdominal tenderness

Blood tests

evaluate overall health and organ function

Faecal tests

microscopy, parasite screening, culture, or PCR

Imaging

abdominal ultrasound or endoscopy to assess mucosal changes

Advanced imaging (CT) or endoscopic biopsy if further investigation is needed

04How is it treated and managed? Medications, dietary adjustments, and home care

Management of small intestinal dysbiosis focuses mainly on dietary adjustment and targeted treatment. Regular monitoring of symptoms and test results is essential.

Antibiotics or other medications may be prescribed based on test findings
A prescription diet or gradual dietary transition to stabilise the gut microbiome
Regular follow-up visits to monitor clinical signs and recheck laboratory results
Home care includes feeding small, frequent meals and ongoing weight monitoring
Referral to a gastrointestinal specialist or further endoscopic investigation if needed

05What should you prepare before the vet visit? Key information to help your vet quickly identify the cause

Take photos or video of vomiting and stools to bring as reference material

Note the date symptoms first appeared, how often they occur, and how they have changed

Bring details of your pet's current food, treats, and feeding routine

List any medications, supplements, and recent vaccination history

Bring previous test reports or imaging files if available

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.