Herbal Science International Inc is recalling twelve dietary supplements that contain ephedra, aristolochic acid or human placenta because they may present a serious health hazard to consumers. FDA has long regarded dietary supplements containing ephedra as potential health hazards because this botanical contains ephedrine alkaloids. Recent studies have confirmed that ephedrine alkaloids raise blood pressure and cause stress to the circulatory system, effects that are linked to adverse health conditions such as heart attacks and strokes.