The treatment of 122 patients with acute puerperal mastitis consisted in wide opening of a purulent focus, excision of the necrotized tissues and rational drainage of the purulent cavities. After the operation, the antibiotics, intravenous infusion, drugs enhancing the specific and non-specific resistance of an organism were used. Average time of treating in hospital was 11 days, in infiltrative form of mastitis--6.5 days.