Abstract: Zanhuang county of Hebei Province in China is a high risk area of stomach cancer.Our previous studies showed that the carcinog enesis of stomach in this area was closely associated with sterigmatocystin(ST).In the present study,cultured human fetal gastric mucosae were treated with ST and 18 days latey,the gastric mucosae were analyzed with flow cytometer and subcutaneously inoculated into the r-ray irradiated SD newborn rats respectively.The results indicated that the cell numbers in S and G2M phases in cell cycle and Proliferation Index from the ST-treated mucosae increased dramatically compared with that from mucosae in contral group,and the mucosae in the ST-treated explants inoculated into the rats appeared morphologically severe atypical hyperplasia changes,in contrast,the inoculated explants in the control group disappeared completely.These results suggest showed that ST may be a carcinogen for human gastric mucosae.