The therapeutic efficacy of wiferon (recombinant alpha2beta-interferon) versus arbidol was studied in a double-blind controlled study in patients with laboratorily verified influenza. Within the first 24-36 hours after the onset of the disease, wiferon and arbidol reduced the duration of fever, intoxication, and the catarrhal symptoms of the disease as a whole. The agents were shown to have an immunomodulating effect.