AIM: To study the preventive effect of artemether in protection of the people from schistosome infection during fighting against flood in schistosomiasis endemic area of Poyang Lake, Jiangxi Province. METHODS: From the second ten-day period of July to the same period of August, the water level in Poyang Lake raised up due to the torrential rain and 2 embankments, i. e., Zhedi and Jiangtongdi appeared in dangerous situation were selected as the pilots. Sera from the individuals who arrived in the pilot to fight against flood with in 48 h were examined by indirect hemagglutination test (IHA), enzyme-linked immunosorbent assay (ELISA) and McAb-ELISA. The individuals who showed negative in the 3 tests were then selected as the study subjects and allocated randomly to the artemether and the control groups. The first dose of artemether given to the individuals contacted with the infested water with in 11-15 days was 6 mg/kg. If the individual continually contacted with the infested water, the same dose of the drug was given once every 15 days. After the individuals withdrew from the pilot, one more dose of artemether was administered 7-15 days later. Placebo (starch) was given to the individuals in the control group at the same period as in the artemether group. Stool examination was made in the individuals of the 2 groups 40-50 days after last medication for evaluation of the preventive effect of artemether. RESULTS: In Zhedi pilot, the individuals fought against flood for about 1 month. In the artemether group, 99 individuals received 3 doses of the drug were completed the stool examination with egg-positive rate of 4% and no case of acute schistosomiasis was seen. In the control group, 110 people were completed the observation, and 44 of them showed egg-positive with an infection rate of 40%. Meantime, 29 cases were identified as acute schistosomiasis. In Jiangtongdi, the individuals contacted with the infested water for only about 4 h. But in the control group 4 out of 102 individuals showed egg-positive, while in the artemether group 103 people received 2 doses of the drug resulted in none of schistosome infection. No apparent side effect was seen in the people treated with artemether. CONCLUSION: In schistosomiasis endemic area of Poyang Lake, oral artemether given to the people who went to fight against flood showed a promising effect in controlling the acute schistosomiasis and reducing the infection rate.