Quercitin is a bioflavonol found in onions, apples and other produce. A recent study appearing in the Journal of Nutrition (Nov. 2007; Vol 137) found that it may have a blood pressure lowering effect. Of the 41 people who participated in the study, 22 were hypertensive, with average blood pressure of 146/96 and 19 were pre-hypertensive with an average blood pressure of 137/86. Quercitin, given at a dose of 730 mg/day led to reduction in blood pressure.  The subjects experienced a reduction of 7 mmHg in systolic blood pressure and a 5 mmHg reduction in diastolic blood pressure. Other research, published in the September 2007 issue of Atherolsclerosis, found quercetin and its metabolites may help prevent chronic inflammation leading to cardiovascular disease, via their effect on cells lining the blood vessels.