As a traditional prescription of Tibetan drug,Sanweidoukou decoction could be made from boiling herbal medicine cardamom,cumin,piper longum with yak milk together.It is reported to possess therapeutic efficacies against various diseases including Alzheimer′s disease(AD).However,its composition is still unclear due to its complex constituents with different polarities and volatilities.The principal objective of this research is to investigate the chemical constituents of the decoction.Considering different physicochemical properties of various components,gas chromatography tandem mass spectrometry(GC-MS) and ultra performance liquid chromatography coupled with high resolution mass spectrometry(UPLC-HRMS/MS) analysis were performed.As a result,99 compounds were identified and confirmed as monoterpenes or oxygenated monoterpenes from cardamom and cumin,such as eucalyptol,and alkaloids from piper longum such as piperine,as well as lipids from yak milk like triglycerides,etc.The results obtained provide a good support for further insight into Sanweidoukou decoctions pharmacological mechanism study in AD treatment.