The present paper deals with the studies on the effect of some long-chain alcohols and fatty acids in inhibiting the primary infection of the virus TMV in tomato plants.The tested long-chain alcohols were nonyl,decyl,undecyl,dodecyl,tetradecyl,hexadecyl,octadecyl alcohols.The fatty acidstested were docosyl acid,sodium docosylate,a mixture of fatty acids and a preparation,NS-83.The fatty acids contained in olinavew birdr ape(Brassica campestpis var.oleifera) seed oil are 1.1% docosyl acid,35-36% erucic acid,11~12% arachidic acid,12.4-12.7% linolenic acid,12.7~12.9% linolic acid,11~11.3% oleic acid,2.5% tetracoscnic acid,2% eicosenoic acid,4% lignoceric acid,1.8~2% stearic acid and 3.1% palmitic acid.This mixture of fatty acids has the inhibitory effect on TMV infection of tomato plants nearly equal to that of pure docosyl acid along.The preparation,NS-83,was processed from the mixture of the above fatty acids,and was demonstrated to be more effective and lower in cost than any other inhibitory preparations hitherto used in practical control of virus disease of tomato.In addition,this virus inhibitor seems to possess the ability of inducing toleranee of tomato plants to the infection of both TMV and CMV,but further evidence is needed.