Fenofibrate is one of the best options for treating hypertriglyceridemia. In the majority of patients, fenofibrate lowers triglycerides (TG) by 24-55% and improves HDL- and LDL-cholesterol. However, the response to fenofibrate is highly variable and currently there are no screening tests to identify poor responders. Genetic and environmental factors may explain the high variability in response. Although exploratory in nature, this study is of clinical and public health importance because prediction of drug response among those with hypertriglyceridemia is clinically challenging and fenofibrate prescription costs are large ($90 to $130/patient/month); targeting the responsive patients at the outset will help improve treatment outcomes at a lower cost. If successful, the investigators will propose to conduct a large, randomized trial on the effect of pre-prescription genotyping on fenofibrate response.

Inclusion Criteria:

• 19 years old or over dyslipidemic patients designated to receive fenofibrate by their attending physician.
• All patients will be seen at the UAB Diabetes and Endocrine Clinic or Cardiology Clinic.
• Women who are unable to have children because of surgery or other medical reason or are using an effective form of birth control before the study begins and agree to continue to use an effective form of birth control for 6 months after taking the study drug.

Exclusion Criteria:

• Under 19 and/or not a Dyslipidemic patient or dyslipidemic but with a medical condition (e.g., liver or kidney disease) that warrants contraindication of fenofibrate.
• Women who are pregnant, nursing and women who, unless they are unable to have children because of surgery or other medical reason, have not been using an effective form of birth control before the study begins and/or are unwilling to use an effective form of birth control for 6 months after taking the study drug will be excluded from the study.

Women who are seen in the UAB Diabetes and Endocrine Clinic or Cardiology Clinic