Objective. The study included 66 patients with isolated severe traumatic brain injury in the acute period of the disease. Two groups were singled: the 1st group included 35 patients (53 %) who did not have inflammatory complications, the second group had 31 (47 %) people who developed inflammatory complications on the 7,7 ±2,8 days after injury. In the study analyzed of the dynamics of medium-molecular peptides in blood serum, erythrocytes and urine and evaluate the relationship levels of the medium-molecular peptides with the functional ability of the kidneys in the acute period of the severe craniocerebral trauma. Methods. In patients with severe traumatic brain injury measured the spectrum of the medium-molecular peptides in blood serum, erythrocytes and urine through method of the M.Ya. Malakhova and N.I. Gabrielian (1985). Excretory function of the kidneys calculated by the clearance of the creatinine (the formula of Cockcroft-Gault), the index of the syndrome of the endogenous intoxication and the clearance of the medium-molecular peptides. Results. The dynamics of medium-molecular peptides in the blood serum had a two-wave character, immediately after the injury it was caused by the products of destruction of damaged and ischemic brains tissues, and the «second wave» of the increase is associated with the formation of inflammatory complications. Conclusions. In order to assess the level of intoxication in patients with severe traumatic brain injury, it is advisable to include the levels of the medium-molecular peptides in blood serum, erythrocytes and urine into the complex tests of еру endogenous intoxication.