Blood in cat vomit can look very different depending on where it came from and how long it sat in the digestive tract before coming up. Fresh blood appears as bright red streaks or a pink tinge mixed with mucus, water, or food. Blood that has been partially digested in the stomach looks dark brown or black and is often described as resembling coffee grounds. Both forms signal that something is irritating or injuring your cat’s gastrointestinal tract.
Fresh Blood vs. Digested Blood
A small amount of fresh blood often shows up as a light red or pink streak running through otherwise normal-looking vomit. You might see it mixed with clear mucus, bile, or partially digested food. This typically means the bleeding source is in the mouth, throat, or esophagus, since the blood hasn’t had time to interact with stomach acid.
Digested blood looks dramatically different. When blood pools in the stomach before being vomited up, stomach acid breaks down the red blood cells and turns them dark brown or black. The texture becomes granular, similar to wet coffee grounds scattered through the vomit. This appearance points to bleeding somewhere in the stomach or upper small intestine, where the blood has been sitting long enough to be chemically altered. Coffee-ground vomit is easy to miss if you’re not looking for it, since the dark specks can blend in with dark-colored cat food.
Common Causes of Bloody Vomit
The list of conditions that can cause a cat to vomit blood ranges from mild and self-limiting to serious. Gastric ulcers are one of the more frequent causes, and they can develop from chronic use of certain medications, stress, or underlying disease. Inflammatory bowel disease, a condition where the immune system attacks the lining of the digestive tract, causes chronic vomiting that can eventually include blood as the intestinal walls become damaged.
Swallowed foreign objects are another common culprit, especially linear items like string, thread, or ribbon. These can saw through intestinal tissue as the gut tries to move them along, causing internal bleeding that shows up in vomit. Gastrointestinal polyps and, less commonly, stomach cancer can also produce bloody vomit. A condition called feline acute hemorrhagic vomiting syndrome causes sudden vomiting with fresh blood and has been recognized in shelter and cattery settings, though its exact cause is still unknown.
Rodent poison deserves special mention. Cats that eat a poisoned mouse or rat can ingest anticoagulant compounds that block vitamin K recycling in the liver. Without functional vitamin K, the body can’t produce the clotting factors that stop bleeding. This leads to uncontrolled hemorrhage that can show up as bruising, bloody stool, bleeding from the gums, and sometimes bloody vomit. Signs may not appear for several days after exposure, since existing clotting factors need time to deplete.
What to Check at Home
If your cat vomits blood, there are two things worth checking right away. First, look at your cat’s gums. Lift the upper lip and examine the color of the tissue above the teeth. Healthy gums are a light rosy pink. Gums that look pale pink, white, or washed out suggest anemia from blood loss or poor circulation, and that’s a sign the situation is urgent.
Second, pay attention to the volume and frequency. A single episode with a small pink streak is very different from repeated vomiting with visible red blood or dark coffee-ground material. Cats that vomit blood and also show lethargy, weakness, loss of appetite, increased thirst, or diarrhea need prompt veterinary attention. Cornell University’s Feline Health Center notes that even cats vomiting without blood more than once a week should be evaluated.
If you can, take a photo of the vomit or collect a small sample in a sealed plastic bag before cleaning it up. This gives your vet something concrete to assess rather than relying on your description alone.
How Vets Identify the Source
Figuring out why a cat is vomiting blood usually involves several layers of testing. The starting point is typically blood work, a urine sample, and a fecal test to check for infections, parasites, organ dysfunction, and anemia. Abdominal X-rays can reveal foreign objects or obvious structural problems, while ultrasound gives a more detailed view of the stomach and intestinal walls, helping identify thickened tissue, masses, or abnormal sections of the digestive tract.
When initial tests don’t provide a clear answer, endoscopy is often the next step. A thin, flexible camera is passed through the mouth into the stomach and upper intestine, allowing the vet to visually inspect the lining and take small tissue samples for biopsy. This is the standard method for confirming conditions like inflammatory bowel disease, ulcers, and gastrointestinal cancers. For suspected rodenticide poisoning, specific clotting tests can confirm whether the blood’s ability to clot has been compromised.
Colors That Get Confused With Blood
Not everything red or brown in cat vomit is blood. Red-dyed kibble, treats, or colored toy fragments can look alarming when vomited up. Bile, the digestive fluid produced by the liver, is typically yellow or green but can occasionally appear brownish and get mistaken for digested blood. Grass, which many cats chew and vomit, sometimes leaves brownish residue as it breaks down.
The key distinguishing feature of digested blood is the coffee-ground texture: dark, granular specks that don’t dissolve when you smear them. Fresh blood, meanwhile, will look distinctly red and may leave pinkish stains on a white paper towel. If you’re unsure, save the sample. Your vet can test it to confirm whether blood is actually present.