Morphological and histochemical studies of biopsies from the areas of purulent wounds in the process of their treatment in a chamber with regulated environment were carried out. After 2-week course of treatment the purulent wound heals like a pure surgical wound. The granulation tissue contains a small number of leukocytes, the vessel is filled with polymorphonuclear leukocytes. A typical feature is the presence in the wound of lymphoid cell infiltrates in the maturing granulation tissue which indicates enhanced immune processes in the host. The results of treatment show that treatment of purulent wounds in a regulated environment considerably improves the condition of the wound contributing to its purification and stimulating healing processes in it.