Ginseng actually, can have a thinning effect on the blood. Does it raise or lower your blood pressure I don't know. There are some studies that show contradicting evidence. Here is a copy and paste from this web site.
Invalid Link Removed
Cardiovascular Health
Asian ginseng in particular may decrease endothelial cell dysfunction. Endothelial cells line the inside of blood vessels. When these cells are disturbed, referred to as dysfunction, they can cause blockage of blood flow in a variety of ways. This disturbance or disruption may even lead to heart attack or stroke. The potential for ginseng to quiet down the blood vessels may prove to be protective against heart and other forms of cardiovascular disease.
Although not proven, ginseng may also raise HDL (the good cholesterol), while reducing total cholesterol levels.
Finally, there is some controversy about whether, under certain circumstances, ginseng may help improve blood pressure. Ginseng is generally considered to be a substance to avoid if you have hypertension because it can raise blood pressure. In a couple of studies, however, of red Korean (Asian) ginseng, high doses of this herb actually lowered blood pressure. Some feel that the usual doses of ginseng may increase blood pressure while high doses may have the opposite effect of decreasing blood pressure. Much more information is needed in this area before a conclusion can be drawn. And, if you have high blood pressure or heart disease, it is not safe to try ginseng on your own, without specific instructions from a knowledgeable clinician.
Take that for what it is worth.