What are common causes of chronic diarrhea in cats?

Common causes of chronic diarrhea include dietary intolerance or dietary changes, intestinal parasites, chronic intestinal inflammation (such as inflammatory bowel disease), and endocrine disorders. The exact cause requires confirmation by a vet through physical examination, fecal testing, bloodwork, or imaging.

What can I do at home to help the vet make a diagnosis?

Record vomiting and bowel movement frequency at home, take photos of the stools, bring a list of recent foods and medications, and weigh your cat weekly. This information helps the vet understand the disease progression and determine the appropriate tests.

What tests does the vet usually run during the appointment?

Common tests include a physical examination, blood and urine tests, fecal examination, abdominal X-rays, and ultrasound. Endoscopy or intestinal biopsy may also be arranged if needed to confirm the diagnosis.

How long should I wait before taking my cat to the vet for diarrhea?

If diarrhea lasts more than two days, or is accompanied by decreased appetite or weight loss, it is recommended to see a vet within 24–72 hours. Dehydration or blood in the stool warrants an immediate vet visit.

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

Cat Chronic Diarrhea Guide: Symptoms, Diagnosis & Treatment [2025]

Chronic diarrhea in cats lasting more than three weeks may be caused by inflammatory bowel disease, food allergies, infections, or tumors. A thorough diagnostic workup is needed to identify the underlying cause and guide targeted treatment.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ISFM, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Persistent vomiting with inability to eat or drink
•Obvious signs of dehydration such as sunken eyes or skin tenting
•Stool containing bright red blood or appearing dark black — seek care urgently

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

•Loose stools or diarrhea persisting for more than 48 hours
•Ongoing weight loss with noticeably reduced appetite
•Lethargy and significantly decreased activity level

01What symptoms indicate something is wrong?

Common gastrointestinal symptoms of chronic diarrhea and potential warning signs to help owners recognize when veterinary care is needed.

Recurring vomiting or increased frequency of vomiting
Persistent diarrhea or loose stools with increased frequency of bowel movements
Gradual weight loss without an obvious cause
Continued weight loss or poor nutrient absorption despite normal or increased appetite
Signs of dehydration such as dry mouth or decreased skin elasticity
Changes in stool color (dark or blood-streaked)

Seek emergency care immediately if you notice the following symptoms:

⚠️ Persistent vomiting preventing eating or drinking
⚠️ Obvious dehydration such as sunken eyes or skin tenting
⚠️ Fresh blood or very dark (tarry) stools — seek veterinary care immediately

02How do you assess the situation at home? Key observations and when to seek emergency care

Key things to observe and record at home before the vet visit — this helps the vet understand the timeline and possible causes more quickly.

Record the number of vomiting episodes, timing, and what was brought up (including any blood)
Take photos of the stools and record daily frequency and consistency
Weigh your cat weekly and track the weight trend
Note any changes in alertness, activity level, and appetite
Note recent foods, treats, and any diet changes
Compile all records and bring them to the appointment to assist the vet's assessment

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

The vet will start with a basic physical examination and arrange further testing as needed to identify the cause of chronic diarrhea.

General physical exam and hydration assessment (mucous membranes, eyes, skin turgor)

Blood and urine tests to assess internal health and electrolyte levels

Abdominal X-rays to rule out foreign bodies, intestinal obstruction, or organ abnormalities

Abdominal ultrasound to evaluate intestinal wall thickness and abdominal organ changes

Fecal examination, parasite testing, bacterial culture, and PCR testing

Cytology or gastrointestinal biopsy (via endoscopy or surgical sampling)

Endoscopy or referral to a gastrointestinal specialist if needed

04How is it treated and managed after diagnosis? Medications, diet adjustments, and care guide

Treatment depends on the underlying cause and typically involves fluid therapy, dietary changes, and regular follow-up to assess response.

Intravenous or subcutaneous fluid therapy, and assessment of whether hospitalization is needed
Switching to a prescription or highly digestible diet to observe the response
Administering prescribed medications as directed and attending follow-up appointments
Home care including hydration support and a gradual return to normal food intake
Some cases require long-term dietary management and periodic monitoring
Bring observation records and test reports to follow-up appointments for comparison

05What should you prepare before the vet visit? Key information to help the vet diagnose quickly

Take photos of vomit and stools as a record of the condition

Record when symptoms started and how they have progressed over time

Bring a list of recent foods, brands, and treats

List any current medications, supplements, or vaccination records

If you have been weighing your cat at home, bring the weight log

Consider calling ahead to book at a clinic with endoscopy or gastrointestinal specialist capabilities

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)

Fluid deficit

Painful defecation

Intestinal gas

Fresh blood in stool

Enlarged lymph nodes

Loose stool