While the use of herbals is increasing considerably, their efficacy and safety in the humans remains largely unknown. This surge in demand prompts a call for its evaluation. Preliminary data demonstrates that KRG can affect vascular function and our research group has previously shown that Korean Red Ginseng (KRG) can lower blood pressure (BP) in hypertensive individuals. However, it is unknown which dose is the most effective in producing a desired effect. To address this issue, we will test escalating doses of a single Korean red ginseng batch of 0.5g, 1g 3g and 6g on BP in patients with hypertension to determine the most efficacious dose. The most promising dose will be extracted and will advance to next level to be tested again on BP control. The findings of the study may result in better ginseng standardization.

Individuals will arrive at the Risk Factor Modification Centre, St. Michael's Hospital between the hours of 8:00 and 10:00am after a 10 to 12-hour fast on seven separate mornings. They will not have consumed any antihypertensive medications on the study mornings. Each visit will be separated by a minimum of a week. Since the half-life of ginsenosides in humans is less than 24-hours, to allow for a washout of approximately seven half-lives.

In each of the four studies, when individuals arrive at our clinic on a test day they will first have their weight measured and subsequently rest in the seated position. They will then have a catheter inserted into a forearm vein, which will be kept patent by saline. From this device, a registered intravenous nurse will obtain a series of 7ml blood samples. Blood will be taken at 30-min intervals. Subsequently, individuals will fill out forms detailing their pharmacological regimen for the previous 24-hours and their diet (dinner) and activity (sleep, urination, morning routine) regimen for the previous 12-hours. As well, they will detail any adverse events that they experienced since their previous visit. Individuals will then have their office BP measured with a mercury sphygmomanometer until three consecutive measurements of both SBP and DBP <5 mmHg different are obtained. At this point, BP should be steady and subjects will be fitted with an ABPM. Measurements will be taken every 5-min for 30-min, for a total of seven measurements. After the seventh measurement (time 0-min), measurements will be taken automatically every 10-min for 180-min. At time 0-min, treatment or placebo capsules will be consumed. At time 60-min a 360-calorie Ensure® breakfast will be consumed within 5-min. Blood samples will be drawn at 30-min intervals, starting at time 0-min. For 24-hours after the ingestion of treatment, a record of any side effects will be detailed by the participants and then provided to us.

Inclusion Criteria:

• Essential Hypertension

Exclusion Criteria:

• Secondary Hypertension
• Diabetes
• Chronic Kidney Disease
• Liver Disease
• Unstable Angina
• Coronary / Cerebrovascular event in the previous 6 months