Diagnosis of food allergy remains a challenge in dogs and cats, yet clinically it is impossible to distinguish a food allergic cat or dog from an animal suffering from an allergy to dust mites and/or pollens. The only reliable method to diagnose food allergy is a strict and exclusive avoidance diet of +/- 8 weeks followed by a systematic reintroduction of different proteins to establish their allergenicity. The poster presented at the World Congress of Dermatology in Sydney (virtual format) shows the interest of using a highly hydrolysed food for the diagnosis. As a reminder, blood tests are currently of no value for the diagnosis of food allergy in dogs and cats.