Objective: To analysis effect of Ruanjian Sanjie (RJ) prescription on pharmacokinetic behavior of 5-fluorouracil (5-Fu) in rats. Method: Rats were divided into two groups

one group was given 5-Fu only and the other one was given 5-Fu and RJ prescription together.Plasma samples were separated and extracted by 10% perchloric acid solution

HPLC was employed to determine the content of 5-Fu with mobile phase of 0.01 mol·L-1 potassium dihydrogen phosphate

a flow rate of 0.8 mL·min-1 and detection wavelength at 265 nm.Pharmacokinetic parameters were calculated by WinNonlin 5.2.1 software with non-compartmental model. Result: RJ prescription could obviously reduce Tmax [the combined group was (0.381±0.075) h and the single group was (0.514±0.122) h] and apparent volume of distribution [the combined group was (5.915±1.196) mL and the single group was (11.307±5.393) mL] of 5-Fu in rats

but no obvious changes on other parameters. Conclusion: RJ prescription can promote absorption of 5-Fu in rats by intraperitoneal injection

while inhibiting trend of 5-Fu distribution from blood to tissues.