The in vitro schistosomicidal activity of curcumin (doses ranging from 5 to 100 μM) was carried out against Schistosoma mansoni adult worms. Curcumin (at 50 and 100 μM) caused death of all worms. When tested at the doses of 5 and 20 μM, it decreased the worm viability in comparison with negative (Roswell Memorial Park Institute (RPMI) 1640 medium alone or RPMI 1640 medium with 10% dimethyl sulfoxide) and positive (heat-killed worms at 56°C or praziquantel 10 μM) control groups. All pairs of coupled adult worms were separated into individual male and female by the action of curcumin at the doses of 20 to 100 μM. When tested at 5 and 10 μM, curcumin reduced egg production by 50% in comparison with the positive control group. It is the first time that the schistosomicidal activity has been reported for curcumin.