Food allergies are quite commen in dogs and are due to hypersensitivity reactions. The exact immunopathogenesis is not known and although many authors suggest that this is mainly IgE mediated, onset of clinical signs, diagnostic tests and treatment suggest that often a delayed tape of hypersensitivity is involved. The aim of this proposal is to characterise lymphocytes and cytokines involved in the immunopathogenesis and use this to improve diagnosis in patients.