Inhibition of hypersensitivity reactions by a new drug, N(3',4'-dimethoxycinnamoyl) anthranilic acid (N-5').

N (3', 4'-dimethoxycinnamoyl) anthranilic acid (N-5'), a new antiallergic drug, can be taken orally, has low toxicity, and is a potent inhibitor of homologous passive cutaneous anaphylaxis (PCA) both in rats and in guinea pigs. Anaphylactic mediator release from guinea pig lung was decreased by the drug in vitro. Although reversed cutaneous anaphylaxis and Arthus type reactivity were moderately inhibited with N-5', this agent did not inhibit the Forssman systemic reaction or contact dermatitis. N-5' is considered to be clinically applicable to certain allergic-related diseases, in particular asthma caused by reaginic antibody.