Niacin, or vitamin B3, is known to improve cholesterol disorders and is the most effective drug to raise HDL, or the "good cholesterol". The use of niacin has been limited because of a peculiar adverse effect referred to as "flushing', which consists of redness, warmth, tingling and burning. A recent animal study suggests that flavonoids may prevent flushing due to niacin better than drugs like aspirin. The ANTI-FLUSH study is being done to assess whether a presently available dietary supplement known as quercetin, which is a flavonoid, can reduce the flushing that occurs with niacin. We will also assess whether using quercetin to prevent flushing from niacin, can improve how niacin lowers cholesterol.

This study involves people between 21 and 75 years. It will be conducted over a period of 8 weeks, with 4 visits, each separated by 2 weeks. The duration of each visit is 9-10 hours. We will test a different dose of quercetin in each visit.

Inclusion Criteria:

1. Men and women from the age of 21 to 75, inclusive - 16 subjects, 8 men, 8 women.
2. Ability to understand and agree to informed consent.
3. Are reliable and willing to make themselves available for the duration of the study and are willing to follow study procedures.

Exclusion Criteria:

1. Contra-indications or known intolerance to the study medications.
2. History of congestive heart failure, carcinoid, rosacea, renal failure (GFR<60 ml/min/m2).
3. Active liver disease.
4. Active diabetes (defined as any history of type 1 diabetes, or history of type 2 diabetes plus one or more of the following: fasting glucose>= 126mg/dL at screening or use of anti-diabetic medications within 12 months, or glucose>200mg/dL 2 hours after a 75 g oral glucose challenge within 12 months.
5. History of major surgery within the past 6 weeks, or anticipated major surgery during the course of the study, or any history of organ transplant.
6. History of drug abuse within the past 3 years, or regular alcohol use of greater than 14 drinks per week.
7. Women who are pregnant, plan to conceive or lactate.
8. Peri-menopausal women or women currently experiencing flushing.
9. Currently taking vasoactive medications, anti-hypertensives, anti-histamines, Selective Serotonin Re-uptake Inhibitors (SSRIs), NSAIDS, oral steroids, leukotriene inhibitors, supplemental quercetin and > 50mg niacin.

All study participants