Therapeutical action of mexidol as compared to piracetam was evaluated in groups of patients with tick borne encephalitis in the acute period of disease. Mexidol was administered as add-on to antiviral treatment in 72 patients while 89 patients received piracetam. The drugs were introduced intravenously during the first 10 days and then were given as tablets during 2 months. Based on these results, we can recommend the inclusion of mexidol in the pathogenetic treatment (fever symptoms) of tick born encephalitis. The use of mexidol as compared to piracetam led to more pronounced positive changes, higher percentage of favorable outcomes and lower frequency of residual signs.