Glossary

Prescription diet

A food formulated to help manage a medical condition such as kidney disease or food allergy, fed under veterinary supervision.

Also called: therapeutic diet, veterinary diet, vet diet, Rx diet, renal diet, urinary diet, gastrointestinal diet

A prescription diet, also called a therapeutic or veterinary diet, is a food designed as part of managing a medical problem. There are diets for kidney disease, urinary stones, digestive disorders, obesity, diabetes, heart disease, joint disease and food allergy, and each changes nutrients such as protein, phosphorus, sodium, fat or fiber on purpose.

They are sold through veterinary clinics or with a vet's authorization. The word prescription is used by the pet food industry and does not mean the food contains a drug, though a vet's approval is expected.

Because these foods change nutrients for a specific condition, they can be wrong for a healthy dog or a different problem. Use one only on a vet's advice, follow the feeding plan, and recheck regularly, since needs change as the condition does.

Last reviewed November 8, 2026

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Related terms

Chronic kidney disease A gradual, permanent loss of kidney function that causes increased thirst and urination, weight loss and poor appetite, mainly in older dogs. Food allergy An immune reaction to a protein in the diet that usually causes itchy skin and ear problems, and sometimes digestive upset. Hydrolyzed protein diet A veterinary diet whose proteins are chopped into pieces too small for the immune system to recognize, used to diagnose and manage food allergy. Limited-ingredient diet A food built around one protein and one carbohydrate source to reduce exposure, often used to look for a food allergy.