The virucidal effect of aqueous extracts of a number of plants was studied in tick-borne encephalitis (TBE) virus titration in SPEV cell culture in microplates, as well as their capacity to induce resistance in virus-infected mice. The aqueous extracts of ledum, motherwort, celandine, black currant, cowberry and bilberry inactivated TBE virus practically completely, and those of St. John's wort, pot marigold, tansy, chamomile, milfoil, and inula only partially. Studied in vivo, the extracts of motherwort, ledum, tansy and black currant induced resistance of mice to TBE virus infection assessed by the increased survival rate of the animals and significant prolongation of the average longevity. The degree of antiviral activity depended on the preparations used and the routes of their administration.