A total of 60 patients with Hymenolepis nana infection were treated with a single oral dose of praziquantel in two different dose levels. Twenty-nine cases treated with praziquantel in a single dose of 15 mg/kg body weight produced a 100% cure rate. On the otehr hand, 30 out of 31 patients who received a single dose of 25 mg/kg body weight cured completely, but only one case had counts of 200 EPG of feces in each tests on the 20th and 21st days after treatment. The cure rate was 96.8% and the mean egg reduction rate of 99.8 per cent was obtained. Side effects were mild and transitory. In a few cases, abdominal pain, vertigo, headache and diarrhea were complained in a few hours after medication. Clinial hematology, serum biochemistry and urinalysis were performed immediately before and the next day after treatment in all cases. There were no significant abnormalities detected in these tests.
