Typan blue exclusion method and the scanning electron microscope were used to analyze the viability of Ehrlich ascites tumor (EAT) cells in presence of protoporphyrin Ⅸ disodium salt (PP Ⅸ) ultrasonically activated．The level of lipid peroxidation was detected by using thiobarbituric acid reaction method．The cytotoxic effect of PP Ⅸ induced by ultrasound on isolated EAT cells were investigated．The results indicated that no significant effect could be checked out in the cells treated by PP Ⅸ．The cells treated by using ultrasound and PP Ⅸ were damaged more efficiently than the cells treated by using ultrasound alone．The damage could be enhanced with ultrasound intensity,treated time,and PP Ⅸ concentration．Comparing with the group untreated or treated by ultrasound alone,the level of lipid peroxides was notably increased in the group treated by ultrasound plus PP Ⅸ. In summary,PP Ⅸ could enhance the ultrasonically induced cell damage．The damage may be associated with the increased the level of lipid peroxidation．The cell membrane is probably one of the target organelles in this case．

ultrasound； protoporphyrin Ⅸ； Ehrlich ascites tumor cells； cell survival； lipid peroxidation