 METHODS : Large scale application of bromoacetamide in twenty eight counties of four provinces was investigated and its molluscicidal effect in marshland and influence on marshland grass ( Cyperus ) and fishes were observed . RESULTS : High molluscicidal effect of bromoacetamide was found against both snails and snail eggs in various environments . According to the results observed in different fields , the applicable dosage of bromoacetamide is 0 . 0-0 g/m0 for spraying method , 0 . 0-0 g/m0 for immersing method and 0 . 0-0 g/m for immersing in combination with shovelling the turf along the bank . When it was applied in fish-raising ponds or rivers at an applicable dosage , no toxic effect on fishes was found . The spraying dosage of bromoacetamide did not affect the rice seedling but it did some damage to the leaf-tips of marshland grass , however , the grass did turn green and grow . CONCLUSION : Bromoacetamide has proved to be a safe and effective mulluscicde against Oncomelania under various field conditions . 