My cat vomits and has diarrhea about every two weeks; what should I do? (British Shorthair)

Long-term vomiting and diarrhea have many causes needing targeted treatment. Common ones: 1) internal parasites, so get a fecal test and deworm monthly; 2) irregular diet or indigestion, where you fast and withhold water half a day during episodes, then give probiotics and an antiemetic, and feed small frequent or fixed meals.

3) Food poisoning, so ensure good, well-stored food to avoid gut irritation; 4) gastroenteritis, where if regulation brings no improvement, get a full checkup and treat the cause.