High Blood Pressure? Check Out Olive Leaf  Some herbs don’t get the attention they deserve despite an impressive body of research. One of them is olive leaf extract, a powerful herb for high blood pressure. It’s hard to believe, but 22.6% of Canadian adults have high blood pressure. Harder still to believe is that nearly half of Americans over the age of 20 do. Worse, only 24% of Americans with high blood pressure have it under control. Impressive research is piling up