A multicenter, double-blind, double-dummy trial was conducted in 96 general practice patients with upper and lower respiratory tract infection to compare the efficacy and tolerance of roxithromycin (150 mg b.i.d.) and amoxicillin-clavulanic acid (500 mg/125 mg t.i.d.). Good clinical response was obtained in 96% and 95% of cases, respectively, but only 4% of patients receiving roxithromycin volunteered adverse events possibly or probably related to their test treatment, as opposed to 17% of those receiving amoxicillin-clavulanic acid. The results indicate that both drugs are equally effective in the treatment of respiratory tract infection, but that roxithromycin is better tolerated.