The current treatment of diffuse peritonitis comprises surgical release of the source of infection and abdomen sanitization with a targeted antibacterial therapy. One of the promising concepts here is the direct endolymphatic administration of medicines which allows to make higher concentrations of the drug in the regional blood flow. Methods. The study included 48 women aged 18-65 years with diffuse purulent peritonitis. The patients were divided into three groups: 1) 18 patients who postoperatively received standard antibacterial therapy; 2) 14 patients who, in addition to standard therapy, got polyoxidonium and selenase; 3) 16 patients with clinical systemic inflammatory response without organ dysfunction who additionally were treated with endolymphatic administration of merenome, selenase and pentoglobin. Results. The peritonitis was complicated with cellular immunity depression with abnormality in the phagocytic activity of neutrophilic granules and an imbalance of pro-and anti-inflammatory cytokines, especially manifested in representatives of the third group. Using polyoxidonium and selenase caused a decrease in proinflam-matory cytokines concentrations in blood plasma.Endolymphatic drug therapy also has normalized the content of the complement system components in blood, and increase the concentration of interleukin-10, having anti-inflammatory activity. The concentration of cytokines and complement system components during vaginal-cervical secretions after endolymphatic therapy decreased greater than after traditional drug treatment. Conclusions. Endolymphatic drug therapy with the injection of antibiotics, selenase and pentoglobin helps to reduce rapidly the extent of intoxication as well as eliminate the inflammation signs in patients with the diffuse peritonitis. Immunomodulatory therapy has a positive effect on the immune status due to the effect on the lymphatic system at the regional and systemic levels.