The metrifonate standard cure consisted of three doses of 7.5 to 10 mg/kg at a fortnight interval. These repeated doses increase the total cost of the treatment and the number of incomplete cures. We wanted to verify whether a reduced cure gets still a good efficacy. 286 people from three villages situated near Niamey (Niger) where treated at random with either 1, 2 or 3 doses of 10 mg/kg metrifonate. Before treatment the mean egg-output was 40 eggs/10 ml; 4 months later the cure rate was different only between the 1 dose trial and the 3 doses one. Moreover, this rate is low (35.3%) and the mean egg-output is also low (40.3%) for one dose. These results are more significant according to the first mean egg-output level. Below 5 eggs/10 ml, the cure rate is good with 2 or 3 doses (62% and 70%, 4 months later treatment), between 6 and 50 eggs/10 ml the results are still acceptable (55 and 53%). On the other hand, above 50 eggs these results are insufficient even with 3 doses. The single dose does not give sufficient result even in low egg-output.