The present study deals with the preliminaryin vivo screening of suramin and levamisole in rai-Setaria cervi system with special reference to the histochemical changes in the adult worms caused by the drugs. Levamisole proved to be highly effective as a micro- and macro- filaricidal agent. It also appears to be interfering with the normal activity of alkaline phosphatase and glycogen of the adult worms with no apparent effect on its protein content. The drug also causes irreversible paralysis in adult worms. Suramin, though an active pharmacological agent, proved to be completely ineffective on microfilariae as well as on adult worms ofSetaria cervi. Consequently, no notable alterations in the histochemistry of the parasite following suramin treatment were observed.