The effect of mexicor on the functional characteristics of erythrocytes under conditions of post-traumatic period has been studied on rats with traumatic brain injury (TBI) model. TBI leads to an increase in the aggregation of erythrocytes by 143% (p = 0.003), increases the concentration of malonic dialdehyde (MDA) by 40% (p = 0.006), and decreases the electrophoretic mobility of erythrocytes by 22% (p = 0.005) relative to the levels of these indices in intact animals. The administration of mexicor (8.0 mg/day, injected intraperitoneally twice per day for 12 days) upon TBI led to a maximum reduction in the MDA concentration by 61% (p = 0.03) and decreased the aggregation of erythrocytes by 36% (p = 0.01), increased the electrophoretic mobility of erythrocytes by 20% (p = 0.003) on the 3rd day of posttraumatic period, and increased the concentrations of 2,3-diphosphoglycerate by 23% (p = 0.02) on the 7th day as compared to the positive control. The most pronounced changes under the action of mexicor were observed within 3 - 7 days after the onset of TBI. The obtained data show the efficacy of mexicor in the treatment of rats with TBI model, which is manifested by a 40% (p = 0.02) shorter period of recovery of the functional parameters of red blood cells in comparison to the positive control.