Florenal' -a new antiviral drug -is the bisulfite derivative of fluorenon-2-yiglyoxai [I]. Florenal' possesses a high antiviral activity in relation to the influenza virus (type A, strain PRS) in vitro and in experiments on chick embryos, to herpes simplex virus in the model of experimental herpetic keratitis of rabbits, and to the adenovirus in cell culture [1-2]. In a clinical study of the therapeutic action of florenal' at ophthalmologic, dermatologic, and stomatologic medical institutes, its effectiveness has been shown in the treatment of viral diseases of the eyes: herpetic keratitis and adenovirus keratoconjunctivitis [3, 4]; viral diseases of the skin: in vascular acute and recurring herpes simplex and flat and common warts; and also of viral diseases of the mucous membrane of the oral cavityacute herpetic stomatitis and recurring aphthous stomatitis . Medicinal forms of florenal' with a prolonged action have been developed . Florenal' has been recommended by the Pharmacological Committee at the Ministry of Health of the USSR for local application in the treatment of viral diseases of the eyes, skin, and mucus membrane of the mouth.