Traditional Chinese medicine has been used for preventive and therapeutic for thousands ofyears in China;however,most of the detailed herbal pharmacokinetics are still unknown.Conventional pharmacokinetic data provide drug concentration of protein-bound andprotein-unbound forms,however only protein-unbound form drug concentration serves aspharmacological active form for absorption,distribution,metabolism and elimination.Microdialysis is a real-time and continuous sampling technique to collect small molecules ofanalytes with protein-unbound form for biological samples. This technique allows simultaneous invivo multiple site sampling in various biological organ, tissue or fluids; such as blood, brain, bile,liver and muscle…etc from a single experimental animal.