If your cat has any allergies or may be allergic to certain ingredients, it is essential to read the food's descriptions and components before feeding it to your cat. Some ingredients are detrimental to a cat's health and affect their digestive system, so watch out for those.  Your cat might show an allergic reaction that you were unaware of after eating the cat food and treats. The advised action is to take your cat to the veterinarian for a check-up and determine what might have caused the hypersensitivity.