A pilot study was undertaken in order to assess the relationship between selenium status and occurrence of colon cancer in a selected population group. The opportunity for starting the programme occurred in 1992 after some information attained from health control laboratories that noted human colon cancer death rates much higher than normal in a well defined geographical area of central Italy (province of Terni). Element levels in serum and healthy and neoplastic colon tissues were determined for twenty subjects affected by the disease. A hydride generation-based method with inductively-coupled plasma atomic emission spectrometry (ICP-AES) detection was developed for the determination of Se in acid-digested samples. The mean values observed in the three types of samples led to the following conclusion: i) Se levels in serum of subjects affected by colon cancer are significantly lower (0.063 +/- 0.018 microgram/ml) than those reported previously for the national average (0.089-0.093 microgram/ml); ii) there is a considerable difference in Se levels between the healthy and neoplastic tissues (0.098 +/- 0.030 microgram/g vs 0.158 +/- 0.065 microgram/g).