Abstract: Through the experiments of inhibitory effects of water extracts from 10 Chinese herbal medicines on Microcystis aeruginosa, Galla chinensis was selected with strong effect. The results showed: the maximum specific growth rate of inhibition on M.aeruginosa by water extract from G.chinensis was 0.834 d^-1, the inhibition on chlorophyll a was significant with long duration. After 3 h treatment by low concentration group of 50 mg·L^-1, the inhibition rate was higher than 50%. After 24 h treatment by high concentration groups of 500 and 1 000 mg·L^-1, the inhibition rate was higher than 90%. Algal inhibition of G.chinensis figured out the characters of rapidity, sustainability and stablity, which has a great prospect of application in controlling water bloom.

Key words: Chinese herbal medicine, Galla chinensis, Microcystis aeruginosa, water bloom