A clinical evaluation of N-5' with perennial-type allergic rhinitis--a test by the multi-clinic, intergroup, double-blind comparative method.

N-(3,4-dimethoxycinnamoyl) anthranilic acid (N-5'), a new orally useable mast cell stabilizer, was investigated for its efficacy, safety and usefulness in the treatment of 302 patients with perennial nasal allergy by an intergroup, double-blind comparative test using disodium cromoglycate (DSCG) and an inactive placebo as control. The results indicated that N-5', as a mild mast cell stabilizer, was comparable to DSCG in efficacy and minimum in side effect.