Objective: To investigate whether the absorption of shikonin can be enhanced by using shikonin microemulsion. Method: The uptake and intestinal permeability of shikonin and shikonin microemulsion were observed by using single-pass intestinal perfusion model and reverted gut sac method. Result: The shikonin microemulsion could be absorbed in whole intestinal segments. The absorption rate constants(Ka) of shikonin microemulsion at duodenum

jejunum

ileum and colon was 0.213 4

0.221 8

0.217 6

0.221 1 min-1

respectively;the apparent permeability coefficients(Papp) of was 0.035 69

0.036 37

0.036 32

0.037 27 cm·min-1. Ka and Papp at colon were significantly higher than that at the other regions of intestine(P<0.001). Ka of shikonin microemulsion in intestine had no significant difference in the range of 15-60 mg·L-1.The uptake and absorption rate of shikonin microemulsion increased with 106.1%; the permeability coefficient with 123.02%. The absorption process obeyed the Fick's law in the range of 15-60 mg·L-1. Conclusion: The absorption shikonin microemulsion is enhanced by increasing the permeability through a passive mechanism.