A clinico-laboratory study of miramistin, a new antiseptic was carried out. Susceptibility of 236 bacterial strains to miramistin was tested and its therapeutic efficacy was followed up in 10 patients with purulent inflammatory affections of the locomotor system treated locally. After an 18-hour exposure of the strains to a 0.01 per cent solution of miramistin only 9.3 per cent of the isolates (mainly staphylococci) remained viable. Gram-negative cocci died in 6 hours and streptococci died in 1 hour. The local treatment of the wounds on the average for 14 days provided lower dissemination of the pathological foci. In the majority of the patients there was stated primary union of the wounds. On the whole, the results were good in 7 patients, satisfactory in 2 patients and unsatisfactory in 1 patient. No side effects were recorded. Miramistin may be recommended as an antiseptic for the local treatment of infected wounds in traumatologic and orthopedic patients.