The BH strain of Schistosoma mansoni was found to be highly susceptible, to hy cant hone (1 x 80 mg/kg), oxamniquine (1 x 100 mg/kg) niridazole (5 x 100 mg/kg), praziquantel (1 x 100 mg/kg), oltipraz (5 x 125 mg/kg) and amoscanate (1 x 300 mg/kg) and is therefore a good reference strain for chemotherapeutic trials. By contrast, the MPR-1 strain was shown to have developed resistance to oxamniquine without ever having been dosed with oxamniquine. Other oxamniquine/hycanthone resistant strains were shown to have maintained their resistance and a strain believed to be partially resistant to oltipraz was evaluated.