If food is not digested properly, it can ferment in the intestine, producing hydrogen and carbon dioxide. The common mistake made in home preparing meals for cats which cause indigestion is the expectation that foods good for humans are good for cats as well, resulting in very uncomfortable consequences for the cat with none of the well meant benefits. Combination of cooked and raw meats in the cat's meal. Adding canned fish to raw meat foods. Adding dairy, like milk or yogurt to the cat's meal.
Many cats are completely unaffected by any of the above mentioned points, but equally many are.
The symptoms of indigestion may also have a medical condition as the underlying cause, such as an intestinal obstruction, peptic ulcer, or a disorder of the pancreas, liver, or gallbladder, and a veterinarian should be consulted in addition to re-evaluating the cat's diet.