Blackfoot disease was prevalent in a limited area on the southwest coast of Taiwan, where artesian well water containing arsenic (median = 0.78 ppm arsenic) had been used for many years. Previous studies of arsenic exposure in the blackfoot disease endemic area have been focused on malignant tumors. We, therefore, conducted this study to analyze mortality of all death causes in blackfoot disease endemic areas and to determine other neglected cancers or noncancer diseases related to artesian well water containing high levels of arsenic. We calculated standardized mortality ratios for cancer and noncancer diseases, by sex, during the period from 1971 to 1994 and compared them to the local reference group (i.e, Chiayi-Tainan County) and the national reference group (i.e., Taiwan population). The results revealed marked standardized mortality ratio differences for the 2 reference groups. Greater mortality was found for males and females with bladder, kidney, skin, lung, nasal-cavity, bone, liver, larynx, colon, and stomach cancers, as well as lymphoma than in the local reference population. With respect to noncancer diseases, we found greater mortality for males and females who had vascular disease, ischemic heart disease, diabetes mellitus, and bronchitis than in the local reference group. Mortalities for other diseases--including rectal cancer, cerebrovascular disease, and other diseases--were higher among cases than the local reference group. Our results indicated that the hazardous effect of arsenic is systemic. Diseases related to arsenic exposure included those reported previously by other investigators, as well as diseases reported in the present study.