Vitamin A, E, C and B6 status was studied in 30 patients with myocardial infarction and in 19 age- and sex-matched patients after elective surgery or trauma. Plasma levels of the four vitamins studied were low, remained low or decreased transiently in both groups of patients during the acute catabolic response phase, and began to return to normal after the third day from the start of the catabolic response. These changes in plasma levels are therefore neither of any special pathophysiological importance in nor specific to myocardial infarction.