OBJECTIVE: To identify the active ingredients and metabolites in rat bile after Guangtongxiao decoction (GTX) had been administered via the rectal route.METHODS: Drug-containing bile samples were collected via a catheter in the bile duct and could be used 5 h after rectal administration.The main active components and their metabolites in rat bile following rectal administration of GTX were identified and analyzed using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry.RESULTS: Positive and negative modes were applied to analyze and identify the chemical ingredients in the bioactive fractions of GTX.Eight peaks were identified by comparison with the standard compounds: berberine hydrochloride,dehydrocorydaline,tetrahydropalmatine,corydaline,magnoflorine,magnolol,obacunone and albiflorin.Furthermore,60 metabolites were detected in rat bile based on mass-fragmentation behaviors,and 21 metabolites were reported for the first time.CONCLUSION: Our findings provide a solid basis for further pharmacologic and pharmacokinetic studies of GTX.