Feline Health • Digestive System

My cat has diarrhea. What should I do?

A brief mild episode can occur with diet change or stress, but diarrhea may also reflect parasites, infection, inflammatory disease, toxin exposure, medication effects, or systemic illness.

Veterinarian reviewedUpdated Aug 20, 2026
The key takeaway

Age, hydration, frequency, blood, vomiting, appetite, and overall behavior determine how urgent diarrhea is.

Prompt veterinary care is warranted for bloody or black stool, repeated vomiting, significant lethargy, dehydration, abdominal pain, fever, poor appetite, weight loss, or diarrhea in a young kitten.

Small bowel or large bowel clues

Large-volume diarrhea and weight loss can suggest small-intestinal disease, while frequent small amounts with mucus or straining often point toward the colon. These patterns overlap and are not a diagnosis on their own.

What information is useful?

Note recent diet changes, treats, raw food, medications, deworming history, travel, exposure to other animals, and whether multiple pets are affected. A fresh stool sample may be useful for parasite or other testing.

Should I change the diet?

Sudden repeated diet changes can make interpretation harder. Your veterinarian may recommend a highly digestible or therapeutic diet depending on the case. Human anti-diarrheal drugs can be inappropriate or dangerous for cats.

When diarrhea becomes chronic

Persistent or recurring diarrhea may require fecal testing, bloodwork, imaging, diet trials, and sometimes more advanced gastrointestinal testing. Weight loss and appetite change increase concern.