Aim Total Panax Notoginsen saponin(tPNS) is a traditional herb medicine of Chinese. In this study, we have investigated the release of nitric oxide (NO) from cultured porcine aorta endothelial cells (PAEC) affected by the tPNS for understanding the pharmacological mechanism of tPNS.Methods PAEC were cultured with M199 and compared the morphological appearence of tPNS group with the control under the phase contrast microscope after PAEC exposed to conditional medium (CM) for 24 hours. NO amounts in CM were determinated by the methods of Termin and Green.Results PAEC in tPNS groups were grew normally. The cells of control group were constricted and separated from each other, there were a lot of small vesicles in the cytoplasma. The amounts of NO in CM of tPNS groups were ranged from 350±59 to 410±90nmol·L-1, and compared with the control, the P<0.001. This enhance was ceased by pluinq EDTA in CM. The time course expressed that the amount of NO was raised quickly by pluing tPNS and was maintaining a high level. This effect could stop by adding the EDTA in CM too.Conclusions The results of enhancing the release of NO from PAEC and maintaining the growth of PAEC by tPNS were suggested that the tPNS can playa significant role in some diseases such as atherosclerosis.