Canine food allergy can be defined as a non-seasonal, pruritic skin disorder of dogs that is associated with the ingestion of a substance found in the dog's diet. This study records the use of a proprietary dried fish, corn and soyabased diet for the investigation and maintenance of food allergic dogs when fed initially as a restricted allergen diet and then as a maintenance diet after challenge. All the dogs showed evidence of pruritic skin disease and in addition demonstrated gastrointestinal signs. These included the presence of faecal mucus and blood, tenesmus and increased faecal frequency; all the signs associated with colitis. Both cutaneous and gastrointestinal signs resolved when an elimination diet was fed and could be reproduced when the animal was appropriately challenged. Ten dogs were trailed on a home cooked diet of fish and potato and 10 dogs on the proprietary complete food. All the dogs were challenged to identify their food allergies. Nineteen of the dogs have subsequently been successfully maintained on the proprietary food.