Alterations in content of main inhibitors of proteolysis alpha 1-antitrypsin and alpha 2-macroglobulin as well as activity of neutral proteases in blood serum were studied in herpetic impairment of human and rabbit retina. Unspecific protective reaction of the blood proteolytic inhibitors developed in ophthalmoherpes. In the acute period of the disease content of alpha 1-antitrypsin was increased and the content of alpha 2-macroglobulin was decreased. Slow development of the disease was observed when the content of alpha 1-antitrypsin was decreased at the period of acute inflammation. Estimation of proteolytic inhibitors might serve as an useful test for characteristics and prognosis of herpetic keratitis.