What are the common causes of infectious diarrhea in cats?

Common causes include viral, bacterial, or parasitic infections. Young cats and those with weakened immune systems tend to develop more severe illness. Your vet can confirm the specific cause through testing.

What initial care can I provide at home?

Record symptoms and how often they occur, keep your cat warm, and offer small amounts of water and easily digestible food. If vomiting continues or dehydration appears, seek veterinary care promptly.

When is PCR testing recommended?

PCR may be recommended when a viral infection is suspected or when several cats in a group show similar symptoms, as it helps confirm the pathogen and guide infection control.

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

Feline Infectious Diarrhea in Cats: Symptoms, PCR Testing & Supportive Care [2025]

Feline infectious diarrhea can be caused by a range of pathogens, including viruses, parasites, and bacteria. Kittens are especially susceptible and tend to develop more severe symptoms. Treatment targets the underlying cause and is supported by general supportive care.

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

•Rapid breathing or signs of respiratory distress
•Persistent heavy vomiting with inability to drink or eat
•Persistent diarrhea accompanied by fainting or severe collapse

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

•Noticeably reduced energy and decreased interaction lasting more than one day
•Significant weight loss over a short period exceeding two days
•Repeated vomiting or diarrhea with no improvement

01What symptoms indicate something is wrong?

Feline infectious diarrhea typically presents with gastrointestinal symptoms and general weakness. Severity depends on the underlying cause, the cat's age, and immune status.

Lethargy, reduced activity, and less interaction with people or other pets
Noticeable weakness or drowsiness, moving more slowly than usual
Frequent or persistent vomiting with reduced appetite
Ongoing diarrhea, which may contain blood or mucus
Rapid weight loss or signs of dehydration (poor skin turgor, dry mucous membranes)

Seek emergency care immediately if you notice the following symptoms:

⚠️ Rapid breathing or signs of respiratory distress
⚠️ Persistent heavy vomiting with inability to drink or eat
⚠️ Continuous diarrhea with collapse or severe prostration

02How to assess your cat at home: what to watch for and when to go to the emergency vet

Keeping a careful record at home helps your vet assess the situation quickly and identify possible causes, while initial home management can reduce risk.

Note the timing of any changes in alertness, activity level, or interaction
Log the frequency, content, and timing of vomiting episodes — take photos or video if possible
Photograph or film the stool and note whether blood or mucus is present
Weigh your cat at the same time each day to track any weight changes
If symptoms worsen — vomiting or diarrhea persists, or the cat cannot eat or drink — arrange a vet visit promptly

03How will the vet diagnose the problem? Common tests and examinations

After a physical examination, the vet will order laboratory or imaging tests as needed to identify the cause and gauge severity.

Physical examination

assessing dehydration, temperature, abdominal palpation, and mucous membrane colour

Blood tests

evaluating overall metabolic status, hydration, and organ function

Fecal examination or parasite testing

looking for signs of parasitic or bacterial infection

PCR testing

confirming possible viral pathogens when identifying the infection source is needed

Imaging (abdominal X-ray or ultrasound)

ruling out obstruction, intestinal abnormalities, or other internal conditions

04Treatment and care after diagnosis: medications, dietary changes, and home management

Treatment focuses on supportive care, with anti-infective therapy or further intervention added based on test results. Follow-up visits are needed to monitor recovery.

Medications and a supportive treatment plan are chosen based on test results (determined by your vet)
Maintain or restore hydration — intravenous or subcutaneous fluids may be given at the clinic if needed
Switch to a bland or low-fat diet in the short term, offered in small, frequent meals
Return for follow-up blood or fecal tests as directed by your vet to confirm improvement
If symptoms do not improve or keep recurring, a specialist or imaging assessment is recommended

05What to prepare before the vet visit: helping your vet identify the cause quickly

Take photos or video of any vomit and stool, and note the time each episode occurred

Write down a detailed timeline of when symptoms began and how they have progressed

List recent food brands, any diet changes, and exposure to other animals

Bring any recent test results and a list of current medications or supplements

Use a secure carrier, keep your cat warm, and minimise stress during transport

If PCR or imaging tests may be needed, book a clinic that offers these services

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.