Zinc therapy in Wilson's disease is a lifelong treatment to prevent reaccumulation of copper. Previous reports have shown that in normal male subjects, zinc ingestion has reduced high-density lipoprotein cholesterol level. This finding raises the possibility that lifelong zinc therapy could be atherogenic. In the present work, the effects of zinc therapy on serum lipids over a period of years is evaluated in patients with Wilson's disease. Zinc therapy reduces total cholesterol level by about 10% in both sexes and reduces high-density lipoprotein cholesterol level by about 20% in male patients. The mechanisms of these interesting effects of zinc on cholesterol metabolism are unknown. The coronary heart disease risk factor is not changed significantly by zinc therapy in either sex, and further, it remains below average in these patients after zinc therapy. We conclude that zinc therapy in Wilson's disease is not atherogenic.