OBJECTIVE: To probe into the effects of butylphthalide on pharmacokinetics and mechanism of nifedipine in rats. METHODS: Male SD rats [average body weight was（250±20） g] were selected as experimental animals. The rats were divided into control group and experimental group by gavage administration of nifedipine 10 mg/kg and nifedipine 10 mg/kg combined with butylphthalide 80 mg/kg for pharmacokinetic study. The effect of butylphthalide on the absorption of nifedipine in the intestine of rats was investigated by in vitro flip intestine experiment. The effect of butylphthalide on the plasma protein binding rate of nifedipine was investigated by equilibrium dialysis experiment. The samples of this experiment were all determined by ultra performance liquid chromatography-tandem mass spectrometry. RESULTS: Compared with the control group

the AUC and C

max

of nifedipine were significantly lower and the V/F was significantly higher in the experimental group

with statistically significant differences（P

<

0.05）; the T

1/2

was shorter and CL/F was higher in the experimental group

while the differences were not statistically significant（P

>

0.05）. Butylphthalide could inhibit the absorption of nifedipine in the intestine of rats

and the inhibitory effect of butylphthalide on nifedipine was more significant at the concentration of 16 mg/L and 32 mg/L

which presented a concentration-dependent. Butylphthalide did not affect the plasma protein binding rate of nifedipine. CONCLUSIONS: Butylphthalide can reduce the blood concentration of nifedipine by inhibiting the absorption of nifedipine in the intestine of rats.