PURPOSE: Gastric cancer is the most common cancer in Korea. The principal therapy for this type of cancer is surgical operation along with neoadjuvant or adjuvant therapy. Gastric cancer patients develop disorders such as poor oral intake and indigestion after receiving a gastrectomy. Such patients gradually fall into nutritional disorders. The selection of gastrectomy procedures and anastomosis methods applied differentiate the presence of post-operative complications; and furthermore, whether the application adjuvant chemotherapy causes a difference in the grade of the nutritional disorder. In the past, the survival length was too short after the gastric cancer operation for interest to arise in the post-operative nutritional failure problems. However, current early screening tests have increased the detection rate of early gastric cancers, and the advancements in surgical techniques and immunochemical therapy have lengthened the expected life span long enough to raise the nutritional problems. This aim of this research was to study the changes in the mineral contents before and after a gastrectomy using hair tissues. METHODS: Twenty gastric cancer patients who received operation in Severance Hospital Yonsei University between January and March, 2002, were selected. Hair tissues with a length of 3 cm were collected from the posterior cephalic region before and 3 months after the operation. The collected hair tissues were sent to Tei KOREA CO., LTD. for the levels of 23 different minerals before and after the operation to be examined and measured. RESULTS: The average age was 53.55+/-11.74 years old, and the male and female ratio was 14: 6. Five cases received a total gastrectomy, while the other 15 received a subtotal gastrectomy. Six out of the 20 received post-operative adjuvant chemotherapy. The levels of almost all the minerals were marginally decreased, with the exception of two. The level of sodium had meaningfully decreased while that of molybdenum had increased. CONCLUSION: The mineral contents gradually decreased three month after the gastrectomy has been carried out. The level of sodium significantly decreased, while that of molybdenum increased. Further study and prolonged follow-up observations are essential to detect minerals changes in the evaluation of nutritional changes in those patients having received a gastrectomy.