Abstract: BACKGROUND ＆ AIM: To investigate the relationship between the toxins of Alternaria alternata and the incidence of esoghageal cancer in Linxian. MATERIALS AND METHODS: Alternaria alternata was isolated from grains in Linxian and its toxins from grains and urine from residents in Linxian were examined by the thin-layer chromatography, and results were compared with previous measured levels. RESULTS: ①the rate of contamination by Alternaria alternata in wheat was less than that in 1981 (χ2=359.283，P<0.01). ② the positive rate of AOH in wheat in 2004 were lower than those in 1995 (χ2=5.152，P<0.05). ③the positive rate of AOH in the wheat flour was lower than those in grain (χ2=5.128，P<0.05). ④ 4 out of 99 samples of urine contained AOH ,and 1 of these had AME in 2004. The results were all lower than those in 1992, (χ2=7.082，P<0.01; χ2=14.282,P<0.01 respectively). CONCLUSION: There is an association between the decrease in exposure to the toxins of Alternaria alternata and the lowered incidence of esophageal cancer in local residents.

Key words: Linxian, grains, alternaria alternata, alternariol, alternariol monomethyl ether