PURINA® PROPLAN® VETERINARY DIETS HA St/Ox Hypoallergenic is a complete hypoallergenic veterinary diet for the diagnosis and management of food allergies in cats of all ages, including kittens. Some cats may suffer from food allergy, which can cause skin discomfort and/or digestive upsets. HA is a true hypoallergenic diet formulated with protein that has been broken down (hydrolysed) into very tiny components that are too small to cause an allergic reaction, and a purified carbohydrate source. Such hydrolysed diets are recognised as the best type of food to use during an 'elimination diet trial' when trying to diagnose (or rule out) food allergy. During such a trial, it is important that your cat is fed no other food or treats. HA is also useful for cats with severe bowel disease, such as IBD, as it is highly digestible.