Abstract: Aim ：To study the pharmacokinetic effects of salvianolic acid B(Sal B) on danshensu(DSS) in Danshen injection in rats.Method：Following the intravenous administration of Danshen injection and Danshen injection added with Sal B to rats， the plasma kinetic study，tissue distribution and urine excretion were studied.The plasma kinetic study was also investigated by giving DSS and DSS in combination with Sal B to rats.Plasma，tissue and urine drug levels of danshensu were analyzed by LC-MS. Results ：Compared with danshensu given alone，no significant difference of the pharmacokinetic behavior of danshensu was found when danshensu was given in combination with salvianolic acid B.However，compared with Danshen injection given alone，the pharmacokinetic behavior of danshensu changed remarkably when Danshen injection was given in combination with salvianolic acid B which might be caused by the decrease of DSS in kidney distribution and urine excretion. Conclusion ：The pharmacokinetic effects of salvianolic acid B on danshensu depend on the existence of multiple components in Danshen injection.Results suggest that the pharmacokinetic interactions of the multiple components are closely related to the integrity of herbal medicines.