My Cat Has Bloody Mucus

By: Chewy EditorialPublished:

My Cat Has Bloody Mucus


I recently rescued a 7-year-old male cat. Since I’ve had him I have noticed bloody mucus around my house. I checked his litter box and saw some in his stool and some droplets outside his cat litter box. I’ve taken him to a vet and he didn’t have any parasites, but he is FIV-positive.

He was dewormed by my vet. After still finding the bloody mucus, my vet suggested changing his diet to a more high-fiber cat food. I changed food very gradually so as not to upset his stomach. I’ve been feeding him this new food exclusively for about a month and am now once again finding the bloody mucus. Do you know what could be wrong with him? Thank you so much for your help.


When cats bleed from their stomach or small intestine, the blood gets digested, turning the stool a dark black color, like tar. When cats bleed from their colon (large intestine), it is past the point where digestion occurs, and the blood comes out looking red, like blood. It sounds to me like this blood is coming from your cat’s colon. Also, the colon is lined by cells that produce mucus.

When the colon is irritated, the cells produce excessive mucus. Based on the presence of bloody mucus, I suspect that your cat has colitis. There are several causes of feline colitis, such as intestinal parasites, infection with giardia (a protozoan parasite), inflammatory bowel disease, and stress colitis, to name a few.

Deworming your cat and switching to a high-fiber food is definitely the proper approach, and most cats respond to treatment. FIV puts cats at increased risk for infection, and infectious causes of colitis would have to be high on the list. I would consider testing the feces for giardia.

Overgrowth of large intestinal bacterial is also a possibility. Metronidazole is an antibiotic that is particularly effective at treating both giardia and intestinal bacterial overgrowth. You should ask your vet about this. Your cat might need an occasional short course of this antibiotic when the colitis flares up.

By: Arnold Plotnick, DVM

Featured Image: Konstantin Aksenov/


By: Chewy EditorialPublished: