Abstract: Objective To observe the effect of artesunate（ATS） on the infectivity of Plasmodium falciparum gametocytes（PFG）. Methods 31 volunteers with falciparum malaria and gametocytemia were randomly divided into 3 groups：artesunate (ATS) group (15 cases)， quinine (QN) group (10 cases) and placebo group (6 cases). Each case in ATS group received 6-day course of oral artesunate (200 mg at 0，6 and 24 hours then 100 mg daily for 4 days). Cases in QN group each received 21-dose course of quinine sulfate (500 mg/time) over seven days. Cases in placebo group took 2 tablets of vitamin B composites，three times per day for seven days. Peripheral PFG were counted daily in all cases until the clearance of PFG. Mosquitoes (Anopheles dirus)were fed with venous blood of patients on the 1st，7th，14th，21st and 28th day，respectively. Results All cases in placebo group were PFG positive at the whole course by blood smear examinations. The PFG relative density in ATS group were （12.5±3.3）%，（1.2± 0.4）%，（0.3± 0.1）% on 7th，14th，21st day respectively，and the mean PFG clearance time was（22.0±1.4）d. The PFG relative density in QN group were（173.9±47.0）%，（112.5±45.4）%，（32.5±17.8）% at 7th，14th，21st day respectively，and the mean clearance time of PFG was （32.5±2.1）d （t=4.731，P＜0.01). PFG remained positive on the 28th day in placebo group. The infectivity test to mosquitoes showed on 14th day the positive rate in ATS group，QN group and placebo group were 0，35.0% and 48.7% respectively. In ATS group，the sporozoite rate of anopheline mosquitoes were 14.8% and 0 at 7th，14th day，while in QN group，142.0%，98.6% and 20.3% at 7th，14th，21st day respectively. In placebo group，the infection rate of sporozoites remained stable. Conclusion Oral administration of artesunate with a total dosage of 1 000 mg in 6 days inhibits the infectivity of PFG.

Key words: Artesunate, Plasmodium falciparum, Anopheles dirus