Objective: To observe uptake process of Isoliquiritigenin (ISL) in Caco-2 cell. Method: The concentration of ISL in cells was detected by HPLC and the mechanism of ISL absorption in cells was explored by studying the time

pH

drug concentration and inhibitors on the uptake of ISL in cells. Result: ISL in Caco-2 cells uptake was time-dependent. ISL at 4-15 mg ·L-1concentration range of uptake increased linearly

consistent with passive diffusion process. The drug intake amount (0.48±0.006) μg ·mg-1 under pH 8.0 was significantly lower than pH 5.0 (0.98 ± 0.03) μg ·mg-1 (P<0.01).Compared with the control group

ISL cell uptake was significantly higher after additional treatment with verapamil(1.19 ± 0.030) μg ·mg-1

(P<0.01)

sodium azide (1.10 ± 0.004) μg ·mg-1(P<0.05)and 2

4-dinitrophenol(1.17 ± 0.020) μg ·mg-1(P<0.01). Conclusion: The mechanism of ISL absorption in cells mainly was passive transport and P-glycoproteins participates in the conveying process of ISL in Caco-2 cells.