Abstract: This invention is a method of treating cancer, both carcinomas and sarcomas, and viral infections, in particular HIV through the administration of a pharmaceutical composition containing a benzimidazole derivative. The composition is also claimed. The benzimidazole derivative is selected from the group consisting of: wherein X is hydrogen, halogen, alkyl of less than 7 carbon atoms or alkoxy of less than 7 carbon atoms; n is a positive integer of less than 4; Y is hydrogen, chlorine, nitro, methyl, ethyl or oxychloro; R is hydrogen, alkylaminocarbonyl wherein the alkyl group has from 3 to 6 carbon atoms, or an alkyl group of from 1 to 8 carbon atoms and R2 is 4-thiazolyl, NHCOOR1 wherein R1 is aliphatic hydrocarbon of less than 7 carbon atoms, prodrugs, pharmaceutically acceptable salts and mixtures thereof and a pharmaceutically acceptable carrier.