Abstract: PTS, one of the major effective components of Panax notoginseng was found to exertremarked antiarrhythmic activities on coronary artery ligation induced ischemic and reperfused arry-thmias in rats. PTS also reduced the size of myocardial infarct. For iv CaCl₂-Ach induced atrial fibr-illation and/or flutter in mice, PTS produced a significant protective effect. In addition, PTS showedan action of prolonging the life under the condition of normobaric hypoxia.