Seventy-six patients with established atherosclerotic disease were treated daily with either 250 micrograms of chromium orally as chromium chloride or a placebo for a period of 7 to 16 months (mean, 11.1 months). Serum chromium increased from 2.69 +/- 0.09 to 12.12 +/- 0.77 nmol/L (mean +/- SE, P less than .005). Serum triglycerides were lower (1.68 +/- 0.11 and 2.10 +/- 0.14 nmol/L, respectively; P less than .02) in the chromium-treated patients than in the patients who received placebo, and serum high-density lipoprotein (HDL) increased (from 0.94 +/- 0.05 to 1.14 +/- 0.07 mmol/L, P less than .005) in the patients who received chromium. There was no change in serum cholesterol or blood glucose during the study.