A series of chrysin derivatives, prepared by alkylation, halogenation, nitration, methylation, acetylation and trifluoromethylation, were tested in vitro against human gastric adenocarcinoma cell line (SGC-7901) and colorectal adenocarcinoma (HT-29) cells. Among these derivatives of chrysin, 5,7-dimethoxy-8-iodochrysin 3 and 8-bromo-5-hydroxy-7-methoxychrysin 11 have the strongest activities against SGC-7901 and HT-29 cells, respectively. 5,7-Dihydroxy-8-nitrochrysin 12 were found to have strong activities against both SGC-7901 and HT-29 cells.