The clinical efficacy of "Food ichthyenic oil", a new foodstuff, was studied in 129 patients with atherogenic dyslipidemia. The oil was given in a daily dose of 30 ml which contained 8 g polyunsaturated fatty acids of the omega-3 class. All the patients were divided into 3 groups: (1) 44 patients with 5.2-6.5 mmol/l cholesterol; (2) 37 with over 6.5 mmol/l, and (3) 48 with hypercholesterolemia (cholesterol over 5.2 mmol/l and hypertriglyceridemia (triglycerides over 2.3 mmol/l). Following 1-month therapy, all the groups displayed lower low density lipoprotein cholesterol levels and significantly higher high density lipoprotein cholesterol concentrations. After 4-month intake of ichthyenic oil, the levels of total and LDL cholesterol returned to the baseline values, whereas the concentration of HDL cholesterol was significantly higher than the baseline one. Following 12-month therapy, there were 15 and 14% decreases in total and LDL cholesterol, respectively, a 16% increase in HDL cholesterol. The patients from Group 3 exhibited low VLDL cholesterol and triglyceride levels.