Cats occasionally vomit, and while it’s unpleasant, it’s often harmless. However, if your cat’s vomit smells like feces, it could indicate a more serious issue. This type of vomit is not typical and warrants attention.
Dear Tabby 🐾
“I’m used to occasional hairballs or vomit from my cat, but the other day, the smell was awful. It literally smelled like poop. She didn’t seem sick afterward, but I’ve never experienced that before. Is it something serious or just gross?”
— Natalie G., Austin
Tabby Replies 🐱
You’re right to raise an eyebrow, or wrinkle your nose. Vomit that smells like feces is not typical, and it usually means there’s more going on than a simple upset stomach. Whether it happens once or repeatedly, it’s worth investigating.
Let’s look at some of the most likely causes and what each might indicate.
💩 Backflow from the Intestines
The most common reason for poop-smelling vomit is reverse peristalsis, which means digested material is being pushed back up from the intestines rather than just from the stomach.
This usually happens when something in the lower gastrointestinal tract is blocked or not moving properly, causing waste material to reverse course.
If your cat vomits brown liquid with a foul odor, this is often the culprit.
🚫 Intestinal Blockage or Severe Constipation
A bowel obstruction can prevent food and waste from moving normally through the digestive system. As things back up, stomach contents can begin to resemble and smell like feces.
Blockages can result from:
- Hair accumulation
- Swallowed foreign objects
- Intestinal inflammation
- Tumors
If vomiting continues, and your cat is also not pooping, seems lethargic, or has a swollen abdomen, seek veterinary care immediately.
🐱 Gastrointestinal Infection or Disease
A strong odor in vomit can also come from bacterial overgrowth, particularly if your cat has a GI infection.
When bacteria ferment food in the intestines, the result can be a stinky, sour-smelling expulsion that includes bile, digested food, or mucous. Cats with inflammatory bowel disease or parasites may also show these signs.
Look for additional symptoms such as diarrhea, appetite loss, or excessive drooling.
❗ Kidney or Liver Dysfunction
In rare cases, a metabolic issue like kidney disease or liver failure can cause foul-smelling vomit.
Toxins build up in the bloodstream and are expelled through vomiting. The smell may be fecal, chemical, or unusually sour. If your cat’s breath also smells like ammonia, or if vomiting is chronic, get blood work done as soon as possible.
These conditions are serious but manageable when caught early.
🧬 What Science Says: Fecal Smell in Vomit
There are no studies focused specifically on poop-scented vomit in cats, but veterinary sources consistently point to intestinal blockages or GI infections as the most likely causes.
This type of vomit usually contains partially digested material from the small intestine, where nutrient absorption happens. Once that material reverses into the stomach, the result is visually and aromatically unpleasant.
If you are seeing dark brown vomit with a foul odor, that is a signal to involve your veterinarian quickly.
Tabby’s Final Word 🧶
Vomit is never fun to deal with, but vomit that smells like poop is in a category of its own.
This is not just a messy incident. It is your cat’s way of flagging a problem that likely involves the intestines, digestion, or more serious organ function. One event may not mean something critical, but it is not something to dismiss.
When in doubt, collect a sample, take a photo, and call your vet. You are not just keeping your floor clean, you are protecting your cat’s health, one very stinky signal at a time.