Colitis means inflammation of the colon. In cats it may cause an urgent need to defecate, frequent small stools, mucus, straining or streaks of bright red blood. A cat may visit the litter box more often without producing much stool. However, straining can also be associated with constipation or urinary problems, so it is important not to guess the cause.
What to look for in the litter box
Note how often your cat tries to pass stool, the amount produced, and whether it contains mucus or blood. Also monitor appetite, vomiting, weight and energy. If you are unsure whether your cat is attempting to urinate or defecate, seek prompt assessment; a blocked urinary tract can be an emergency, especially in male cats.
Possible causes
Parasites, dietary reactions, intestinal inflammation and other illnesses can contribute to large-bowel diarrhea. Some cases are short-lived; others need a systematic workup. A veterinarian may request a fecal sample and blood work or recommend imaging and further tests when signs persist.
When to seek care
Repeated vomiting, blood with ongoing diarrhea, loss of appetite, dehydration, weight loss or marked lethargy warrants veterinary attention. Kittens and medically fragile cats can deteriorate rapidly. Collapse, severe pain, or straining with no urine passed requires emergency help.
How treatment is chosen
Diet trials, antiparasitic therapy, medications for a diagnosed disorder and other measures may be considered. Antibiotics are not a routine cure for all chronic diarrhea. Never give a cat human anti-diarrheal medicines without a veterinary instruction, and avoid fasting a sick kitten.
For follow-up, keep a consistent diet as directed and track stool changes rather than switching treats or supplements repeatedly. See Merck Veterinary Manual: Colitis and our guide to complete cat nutrition.
Educational information; a clinician should assess persistent symptoms.
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.