Hills prescription diet includes a variety of clinically tested therapeutic foods for treating a variety of different conditions in dogs and cats hills prescription diet canine ud is a dietetic dry food used to help to dissolve urate crystals and cystine uroliths and to promote the reduction of urate oxalate and cystine urolith crystals this food can also be used to help with chronic kidney complaints it only contains a small amount of quality protein to help to reduce accumulation of to