The absorption characteristics of itraconazole, which is an antifungal agent, from intestinal segments in the anesthetized rat i1l situ were investigated in order to design an effective oral drug delivery system. The pH-solubility profile of itraconazole, the rate and extent of absorption of itraconazole, the optimal absorption site(s) of itraconazole and the absorption enhancing effect of sodium cholate on itraconazole were examined in the present study. In situ single-pass perfusion method and recirculating perfusion technique using duodenum(D), jejunum(J) and ileum(I) were employed for the calculation of apparent permeability(Pe) and apparent first-order rate constant(Kobs). respectively. The results of this study were as follows; (1) Itraconazole showed appreciable aqueous solubility only at pH values of below 2.0. (2) pe(cm/sec) decreased in the following order: $D(10.24{pm}1.78{ imes}10^{-4})>J(8.86{pm}0.79{ imes}10^{-4})>I(3.78{pm}0.13 X 10^{-4})$. (3) $Kobs(min^{-1})$ decreased in the following order: $J(17.12{pm}3.19{ imes}10^{-3})>D(13.37{pm}0.6{ imes}10^{-3})>I(11.05{pm}0.91{ imes}10^{-3})$. (4) The solubility of itraconazole markedly increased with the increase of the concentration of sodium cholate. (5) The addition of 10 mM sodium cholate significantly increased the apparent first-order rate constant of itraconazole in the ileum by a factor of 6.8.