Likopide (N-acetylglucosamine-(beta 1-4)-N-acetylmuramyl-alanyl-D-isoglutamine) is a synthetic analog of muramylpeptides, characterized by immunomodulating properties and increasing the nonspecific resistance to infections. Seventy patients with ophthalmic herpes were examined, 35 of these were treated with likopide and 35 were administered placebo. Fifty-two of these suffered from stromal keratitis with ulceration and 18 had no ulcers. The trials were carried out by the double blind test with placebo. Likopide was administered orally in 10 mg tablets twice daily according to the following protocol: 3 days of treatment, 3-day interval, and 3-day treatment. All the patients were administered local specific (acyclovir ointment) and general symptomatic therapy. Immunological studies were carried out before and after therapy. Clinical assessment showed a reliably high therapeutic efficacy of likopide, its total value (excellent and good results) being as high as 88.5%. The mean duration of therapy with likopide was 11.4 +/- 0.4 days versus 15.2 +/- 0.9 days in the placebo group. Judging by the recovery criteria (arrest of inflammation, epithelization of the cornea, resorption of corneal infiltration and edema, resorption of iritis) likopide reliably accelerated healing and ensured a higher increase of vision acuity. Likopide reliably decreased the rate of detection of herpes simplex virus antigen in the involved eye conjunctiva in comparison with the placebo group patients (97.1% of negative cases versus 60%). The drug was well tolerated by the patients, no side effects were observed. Skin allergic tests with likopide showed no drug allergies.