A cat may vomit up blood for a number of reasons, including foreign bodies, such as hairballs; parasites, such as heartworms; and liver or kidney disease, according to Banfield Pet Hospital. Any vomiting indicates a potentially serious medical condition, and the cat should be taken to a veterinarian immediately.
According to Banfield Pet Hospital, other causes of a cat vomiting include the ingestion of a toxin, such as lead or arsenic; a bacterial or viral infection; stomach ulcers; or clotting disorders. If the cat's vomit is streaked with fresh red blood, the blood is from the stomach or upper part of the small intestine. If the vomit looks more like coffee grounds, then the blood has been partially digested, meaning it is from the lower intestine. A cat who vomits displays fatigue, loss of appetite and an abnormal stool, such as diarrhea. Vomiting blood is always an indication of a serious ailment and can be life-threatening. Severe blood loss can result in serious problems with other organs and can lead to death.
The veterinarian is likely to perform a series of tests to determine the extent of blood loss and the cat's ability to form clots naturally, states Banfield Pet Hospital. The tests may include a blood cell count, an internal organ function screen and a fecal analysis. The veterinarian then prescribes anti-vomiting medication.