In the study histologic features of change of granulation tissue of cattle in the course of treat-ment of purulent wounds are considered by various ways of drainage. The research was made in ex-perimental group containing 70 animals, to which membrane drainage and dialysates made of semi-permeable membranes containing multicomponent solutions providing continuous dosed receipt of preparations in an organism were performed. As a semipermeable membrane were used the devices developed by us on the basis of a cellulose corru-gated cover with thickness of the wall of 2 mm and with pore diameter 1.5-3.0 microns. The device was entered into wound cavity of animals at the final stage of operation. Filling of the drainage with the dialyzing solution was carried out in the process of its filling (once a day) within 4-10 days. The group of comparison was made by 48 cows to which known ways of treatment and drainage by tubular drainages were applied. As a result of re-search it was established: morphological changes of granulation tissue of infected wounds in animals when using different methods show that in all cases the process of clarification of pathological center proceeds from purulent - necrotic masses, for-mation of granulation tissue and the epithelization of the defect. The application of membrane drain-age of purulent cavities led to their full self-cleaning with the expressed demarcation zone and to the emergence of healthy granulation tissue. The lay-ers of epithelial cells had the ordered structural or-ganization. The processes of collagenization and epithelialization were balanced, this was displayed in the formation of minor scars. The formation of hair bulbs, sebaceous and sweat glands, showes usefulness of reparative processes in a purulent wound.