Objective:To investigate the absorption kinetics of 3-n-butylphthalide（NBP） in intestines of rats.Method: The intestine in rat was cannulated for in situ perfusion.UV and HPLC were used to determine the concentration of phenolsulfonphthalein and NBP

respectively.The effect of drug concentration and hydroxypropyl cyclodextrin（HPCD） on the absorption had been studied.Result: When the NBP concentration of perfusion solution was increased

no specific absorption was founded in different segment.The Papp for NBP decreased when HPCD was co-perfused in the intestine.Conclusion: Passive diffusion dominates the absorptive transport behavior of NBP.NBP is well absorbed at all segments of intestine in rats.HPCD can inhibit the absorption of NBP in the intestinal segment.