In the present study, the effect of methanol extracts of two plant species, Dizygotheca kerchoveana (Maliaceae) and Azadirachta indica (Araliacaea) were tested on the activity of Schistosoma mansoni worms. Efficacy of two plant extracts compared with praziquantel (PZQ) was evaluated in vivo. The results showed that reduction was 90% in case of PZQ treatment compared to 76.91%, 62.64% after treatment with D. kerchoveana and A. indica extracts respectively. PZQ recorded highest significant number of dead ova into oogram pattern (80±1.80) at 5wk PI. But, good results were obtained by of D. kerchoveana and A. indica methanol extracts (65.00±4.05 & 60.60±3.60, respectively) at 3wk PI. Efficacy of the plant extract showed a significant (P<0.01) reduction in ova to 91-96.20% in intestine, 83.36-91.24% in hepatic tissues as compared to PZQ (10-66.50% & 1.14-80.64%, respectively). Reduction in hepatic granuloma
diameter at 3wk PI was significantly (P<0.01) reduced in group treated with D. kerchoveana (40.43% & 38.30%) as compared to PZQ (8.70% & 11.7%). Sera were assayed by ELISA for IgM & IgG levels. Highly significant (P<0.01) increase in Igs levels in all infected treated or untreated groups was at 3wk & 5wk PI as compared to normal mice.