Experimental research was undertaken to investigate the use of amixin in prevention, emergency prevention schemes and treatment of mice infected with West Nile fever (WNF) agent, strain Eg-101; the results are indicative of the drug efficiency both in its peroral and subcutaneous administrations. Amixin was shown to be most effective in the former case when administered, 10 mg/kg, in 96 hours before mice were infected as well as during the entire incubation period: lethality protection--46%. In the latter case, the drug was effective, when 3 administration schemes were in use, 10 mg/kg. The maximum degree of protection efficiency was registered with amixin administration according to the emergency prevention scheme: lethality protection--33%. The drug suppresses effectively the WNF virus reproduction in cerebral tissues.