Abstract: ObjectiveTo observe the anthelmintic efficacy of different therapeutic course of mebendazole on trichuriasis.MethodsFour hundred and twenty patients with single trichuris infections or mixed infection with ascaris or hookworm in Shanghai suburb were randomized into 3 groups and treated with 800mg mebendazole in differnet course.(Group A:Adaily dose of 200 mg mebendazole for 4 days;Group B:Adaily dose of 400 mg mebendazole for 2 days;Group C:A daily dose of 300mg albendazole for 2 days as control).Stool reex amination by Kato-Katz was done in 2 week and 4 week after treatment.ResultsThe rate of egg negative conversion of group A(92.07%)was higher than that of group B(88.04%,P<0.05)after being treated for two weeks, but no difference at 4 weeks;the date of group C(72.45%-76.14%)was lower than the group A and B(P<0.01 and P<0.01).The rate of egg reduction rate after treatment was all above 95% in 3 groups.The cure rate against Ascaris of both drugs being 91.67%-96.43% 4 week afte treatment and no statistic difference in 3 groups.The side effects were few and mild.ConclusionThe efficacy of 800mg mebendazole in 2 day or 4 day course was more than 91% on Trichuriasis.Mebendazole had better effect on expelling trichruis than albendazole.