Objective: To investigate rat intestinal absorption characteristics of total flavonoids from Hippophae Fructus. Method: In vitro everted gut sac model and in situ rat single-pass perfusion model were adopted

the contents of quercetin

kaempferol and isorhamnetin were determined by HPLC

rat intestinal absorption parameters of total flavonoids from Hippophae Fructus were calculated. Result: The best absorption parts of quercetin

kaempferol

isorhamnetin was ileum

ileum and duodenum

respectively.Absorption rate constant (Ka) of these three ingredients were 3.405×10-2

3.649×10-2

5.671×10-2

respectively.Ka and apparent absorption coefficient had no significant difference when the concentration of total flavonoids from Hippophae Fructus was 50-200 mg·L-1.A positive correlation was found between drug concentration and accumulated absorption amount. Conclusion: Absorption characteristics of these three main flavonoids components were consistent

all complied with the first order absorption kinetics

absorption mechanisms of them were passive diffusion

and they had specific absorption site in small intestine.