In the Helsinki Heart Study, which was a large placebo-controlled study with 4081 male subjects, 40 to 55 years of age, with primary dyslipidaemia (predominantly raised non-HDL cholesterol +/ - hypertriglyceridaemia), but no previous history of coronary heart disease, gemfibrozil 600 mg twice daily, produced a significant reduction in total plasma triglycerides, total and low density lipoprotein cholesterol and a significant increase in high density lipoprotein cholesterol.