To investigate the relations between salted pork (SP) from Zhuanghe (a high risk area of stomach cancer in northeast China) and stomach cancer three studies had been done, including the mutagenicity of SP, the effect of SP on the gastric mucosa of residents in Zhuanghe area who had consumed SP for 10-30 years and the mucosal lesions of dogs taking SP. The results showed that the extract of SP was a strong mutagen in strain TA98 and led to increased micro-nuclei rate (MNR) and micro-nuclei cell rate (MNCR) of V79 cell at a dose range of 20-80 mumol/ml. There were dose-effect relations between SP and MNR, MNCR. The results also indicated that pathological changes of gastric mucosa of residents who consumed SP had remarkable difference from those of the control group. In people who had consumed SP for 10 years, mucosal lesions including necrosis and erosion were seen; for those consumed SP for 10+(-)20 years, there were hyperplasia and dysplasia and those for 20+(-)30 years different degrees of dysplasia and even malignant change could be observed. The research also found that SP had damaging effect on gastric mucosa in dogs taking SP. The mucosal lesions became more severe with time of feeding SP. The conclusion is that SP is a strong mutagen, long-term exposure to SP may result in repeated gastric mucosal damage and repair, and finally in severe dysplasia and malignancy.