OBJECTIVE To evaluate the clinical efficacy of dihydroartemisinin-mefloquine on acute uncomplicated falciparum malaria. METHODS Fifty-four patients with symptomatic falciparum malaria were allocated to receive oral dihydroartemisinin at a single dose of 120 mg on day 1, followed by mefioquine, 750 mg and 500 mg on days 2 and 3, respectively. Follow-up was performed on days 1, 2, 3, 4, 7, 14, 21, and 28. RESULTS All patients had a rapid initial response to treatment. The parasite clearance time (PCT) after treatment was 30.7 +/- 3.6 hours. The fever subsidence time (FST) after treatment was 21.2 +/- 2.8 hours. Two patients had a recrudescence 21 and 25 days respectively after the disappearance of parasitemia, hence the recrudescence rate was 3.7% and the cure rate was 96.3%. No serious adverse effects were observed, only mild and transient nausea, vomiting and loss of appetite. CONCLUSIONS A combination of dihydroartemisinin and mefloquine is effective in the treatment of acute uncomplicated falciparum malaria.