This study is a non-interventional (observational) study in Japan to confirm the safety and efficacy of Zetia when administered alone or in combination with other lipid-lowering drugs in daily medical practice throughout a 52-week period. It is being conducted as a post-approval commitment, in accordance with the Ministry of Health, Labour and Welfare's guideline on Good Post-marketing Study Practice.

Post-marketing surveys are not considered applicable clinical trials and thus the results of this survey will not be posted at its conclusion. The results will be submitted to public health officials as required by applicable national and international laws.

The population will be selected from 200 institutions in Japan.

Inclusion Criteria:

• Subjects who have hypercholesterolemia, familial hypercholesterolemia, or homozygous sitosterolemia will be considered for this study.

Zetia monotherapy patients must be treated with Zetia alone.

Zetia combination therapy patients must be treated with Zetia in combination with other lipid-lowering drugs for hypercholesterolemia.

Exclusion Criteria:

• Patients with a history of hypersensitivity to any ingredient in Zetia
• Patients with serious hepatic function disorder should not be treated with Zetia in combination with an HMG-CoA reductase inhibitor.

The population will be selected from 200 institutions in Japan.