Fatal cardiomyopathy in a patient who received home parenteral nutrition (HPN) for eight years is reported, and the relationship of selenium deficiency to cardiomyopathy and other adverse effects is discussed. A 42-year-old white man with Crohn's disease who was receiving HPN was admitted to the hospital with severe chest pain and dyspnea. During the three days following admission, his symptoms of congestive heart failure and compensated metabolic acidosis persisted despite treatment. On hospital day 6, the patient developed increased ventricular irritability and refractory ventricular fibrillation and died. At autopsy, the heart weighted 500 g, all chambers were dilated, and the myocardium was grossly flabby. Extremely low concentrations of selenium (5-12% of normal) were found in plasma, heart, liver, and kidney tissue samples. The pathological findings in this patient were similar to those in two previously reported cases and strongly suggest that the fatal cardiomyopathy was secondary to selenium deficiency. Selenium is an integral part of the enzyme glutathione peroxidase, which plays an important role in the metabolism of tissues and organs. For metabolically stable patients receiving total parenteral nutrition, the suggested selenious acid dosage is 25-60 micrograms/day for adults and 1.4-30 micrograms/kg/day for pediatric patients. In selenium-depleted adults, a dosage of 100 micrograms/day administered intravenously for 21-31 days has been recommended to reverse symptoms. All HPN patients and hospitalized patients receiving extended parenteral nutrition should be monitored for selenium deficiency and given supplements if necessary.