Abstract: AIM:To identify and quantify the major metabolites of salvianolic acid B(SAB) after intravenous injection in rats.METHODS:LC-IT/TOF-MS was used to identify the metabolites in rat bile,plasma,and urine;LC-MS/MS was used to quantify the two major metabolites.RESULTS:In rat bile,plasma,and urine,nine metabolites were identified,including methylated metabolites of SAB,lithospermic acid(LSA),the decarboxylation and methylation metabolites of LSA,salvianolic acid S(SAS),and dehydrated-SAS.The t1/2 of monomethyl-SAB and LSA were both very short,and monomethyl-SAB had a larger AUC than LSA in rats.CONCLUSION:Nine metabolites were found,the metabolic pathway was described,and the pharmacokinetic profiles of LSA and monomethyl-SAB were studied,thereby clarifying that methylation was the dominant metabolic pathway for SAB in rats.