Dyslipidaemia is a risk factor for arteriosclerosis. Recent studies have shown that dyslipidaemia is effectively prevented by various polyphenols. In this clinical study (UMIN trial: 000024028), we evaluated the beneficial effects of polyphenols contained in Goishi tea on blood lipid profiles. Seventy-seven subjects with LDL cholesterol (CHO) ≧120 mg/mL were randomly divided into two groups for 12 weeks of polyphenol intake as follows: the Goishi tea group for daily consumption of Goishi tea containing 122 mg of polyphenols and the placebo group for the corresponding consumption of a placebo drink containing 12.2 mg of polyphenols. Intake of Goishi tea polyphenols tended to increase HDL CHO and suppress the elevation of triglycerides. These effects were particularly notable among the subjects with a body mass index <25 kg/m2. These findings suggest that Goishi tea polyphenols may suppress arteriosclerosis and reduce cardiovascular event risk by improving blood lipid profiles and thereby preventing dyslipidaemia.