Various kinds metals are present in varying concentrations in living bodies. They play important roles in the preservation of life functions. Owing to the recent advances in multidisciplinary research on biochemical and nutritional functions of trace elements, their deficiency and excess, etc., close attention is being paid to the importance of trace elements. During nutritional therapy, it is important to check for shortage of trace elements as nutritional indicators. It is known that prolonged nutritional therapy is associated with the risk of developing trace element deficiency.  We recently encountered patients suspected of having trace element deficiency. For a case of selenium deficiency, we added a selenium solution (homemade parental solution) to the solution for intravenous hyperalimentation. For a case of zinc deficiency accompanied by pressure ulcer, polaprezinc (a zinc-containing preparation for the treatment of gastric ulcers) was used. In both the cases, the serum trace element level improved, and the outcome was favorable.  Adequate precautions need to be exercised when the methods of medication, test, etc., are decided upon in the cases of trace element deficiency. Herein, we also discuss problems associated with tests and treatment of patients with trace element deficiency.