The investigator would like to see if aspirin could block niacin-induced flushing by analyzing blood and urine after taking aspirin.

Phase I: Subjects were assigned to either placebo or aspirin groups. They were given 5 days of 81 mg aspirin or placebo. On day 5, they were given a single dose of niacin (600 mg) administered 30 minutes after the last dose of aspirin or placebo. The same subjects came back for cross-over study and were assigned to a different group. There was a 2-week washout period between each treatment. Urine was collected sequentially for analysis

Phase II: The same study subjects come back for an open label one week study. They were given 5 days of taking 81 mg Aspirin, taken once daily, followed by a single dose of 600 mg Niacin on day 6. Urine was collected sequentially for analysis

The purpose of this study is to look at the roles of various blood cells and their contributions of different prostaglandins. The intention is that by better understanding these prostaglandins and various metabolites, it will provide insights into their roles in the cardiovascular system.

Prostaglandins and metabolites are naturally occurring substances found in the blood and urine which can act as markers which can be quantified and studied as we will be doing in this study. Flushing response to niacin will also be assessed by laser doppler measuring blood flow of the facial skin.

Untransformed and transformed data will be subjected to exploratory analysis of variance appropriated for a three factor design with one two period crossover factor and two non-repeated factors. Additionally, volunteer's test(s) for paired observations will characterize the magnitude of the niacin effect on the response variables within selected time points.

Inclusion Criteria:

age between 18-70

• subject must be in good health as based on medical history
• All subjects must be non-smoking, non-pregnant volunteers
• Female subjects of child bearing potential must be using a medically acceptable method of contraception throughout the entire study period. All female subjects must consent to a urine pregnancy test at screening and just prior to the start of each treatment period of the study, which must be negative at all time points.

Exclusion Criteria:

• subjects with any medical condition that according to the investigator may interfere with interpretation of the study results, be indicative of an underlying disease state, or compromise the safety of a potential subject.
• subjects who have received an experimental drug within 30 days prior to the study.
• subjects who have taken medications at least 10 days prior to the study. Birth Control pills are acceptable and shall not be excluded.
• Subjects who have taken aspirin or aspirin containing products for at least 10 days prior to the study.
• Subjects who have taken acetaminophen, NSAIDS, COX-2 inhibitors (OTC or prescription) for at least 10 days prior to the study.
• Subjects who are currently consuming any type of tobacco product(s).
• Subjects who consume high doses of antioxidant vitamins daily (vitamin C > 1000mg, Vitamin E > 400 IU, Beta Carotene > 1000IU, Vitamin A > 5000IU, Selenium > 200mcg, Folic Acid > 1mg) for the 2 weeks prior to the start of the study and throughout the study.
• Subjects who consume alcohol, caffeine or high fat food 24 hours prior to study.

8 weeks