Stomach and intestinal disease is so common in cats that many people think vomiting and ‘furballs’ in an otherwise healthy cat are normal. Vomiting more than once a week, particularly if your cat is losing weight is NOT normal. Furballs are a sign of stomach or intestinal inflammation and should be investigated. There are many causes of vomiting. The easiest to diagnose and treat is an intolerance to a particular food, usually a protein like fish, lamb or beef. If the vomiting stops when your cat is switched to a hypoallergenic diet then a dietary intolerance is the most likely cause. Once the offending protein has been identified you just have to avoid feeding it to your cat. Cats that eat grass or other hard- to-digest plants frequently vomit. Preventing access to the grass may solve the problem but often they are driven to eat grass by an irritated stomach. If a hypoallergenic diet does not eliminate the vomiting we suspect a more serious disease like Inflammatory Bowel Disease (IBD) or a gut cancer. IBD and low grade gastrointestinal lymphoma are quite responsive to treatment. Occasionally more serious cancers are found. An ultrasound may show increased thickness of the stomach or small intestinal wall indicating IBD or lymphoma. Occasionally another problem like a partial blockage or a solid cancer is found. Unfortunately ultrasound does not distinguish between inflammatory bowel disease (IBD) and lymphoma. Biopsy samples of the stomach, small intestinal wall, abdominal lymph nodes, liver and pancreas obtained during abdominal surgery are the most accurate way of distinguishing them. A veterinary pathologist looks at the biopsy sample under the microscope and determines if IBD or lymphoma is present and then classifies them. This information helps us make a treatment plan and predict the response to treatment. Inflammatory bowel disease is caused by a chronically irritated stomach and intestinal lining. The inflammation is sometimes caused by an irritant in the food. Often the cat’s immune system overreacts to components of a normal diet. It is usually very difficult to identify the specific cause. The inflammation interferes with digestion of food and absorption of nutrients. Therefore cats with advanced disease lose weight and try to compensate with an increase in appetite. Treatment includes immunosuppressive drugs such as prednisolone, special diets and vitamin B12 injections. Often, cats get an initial short course of antiparasitic drugs and antibiotics to rule out other irritants of the intestine. IBD is not a curable disease but proper treatment controls it and stops or slows the vomiting and weight loss. Overall, the prognosis is very good. Low grade lymphoma is treated similarly but a low dose chemotherapy drug is added in. Many cats live for years with proper treatment. If dietary intolerance, IBD or low grade lymphoma are left untreated higher grade bowel cancers may develop.