In experimental and clinical investigations, assessment was made of mutagenous, antimutagenous, pro- and antiradical activity of some neurotropic preparations--cerebrolysin, encephabol (pyritinol), nootropil (piracetam), actovegin and cavinton (vinpocetine). In chemical, fermentative and cellular model systems, cerebrolysin inhibited generation of superoxide anion-radical, nitrogen monoxide and final products of degradation of fatty acids. Other preparations showed both anti- and prooxidant effect. The most pronounced anticlastogenic activity during expriments on C. capillaries had a cerebrolysin. Encephabol had the most prooxidant effect and low anticlastogenic activity. The ability of such preparations as ceredrolysin and encephabol to decrease erythrocyte high level with micronuclei in peripheric blood of patients with infantile cerebral palsy (spastic diplegia) was clinically investigated. The modifying effect of preparations was not univalent: it was cerebrolysin that decreased intensivity of aneu- and clastogenesis in patients in a greater degree than encephabol. A protective effect of these preparations was pronounced on the 10th day in group of the boys, and on the 20th day in the group of the girls.