The paper analyzed of investigation datas on the death causes of digestive tract cancer in high-incidence area between 70s and 80s. The results showed that the cancer-adjusted mortalities were 224.14/100000 and 226.66/100000; it was 7 times as high as low-incidence (31.19/100000 and 29.82/100000). In 70s, the cancer death of esophagus, stomach and liver (87.41/100000, 73.93/100000 and 8.59/100000) were 28 times, 10 times and 4 times as high as low-incidence area (3.70/100000, 10.57/100000 and 1.94/100000), respectively (P 0.05). Our results suggest that the nitrate and nitrite contents increase in drinking water and vegetables may be an important risk factor of upper alimentary cancer in high-incidence area.
