Because of low aqueous solubility and slow dissolution rate, cantharidin has a low oral bioavailability. Our research aims to prepare the inclusion complex of cantharidin and beta-cyclodextrin (beta-CD) and accomplish characterization, in vitro and in vivo evaluation. CA-beta-CD inclusion complex was prepared by saturated solution method. The CA was demonstrated by HPLC in vitro experiment and by GC-MS in vivo experiment. CA-beta-CD inclusion complex was characterized by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and nuclear magnetic resonance (NMR). Through complexation with beta-CD, the solubility of CA in neutral aqueous solution was improved significantly. CA-beta-CD inclusion complex also shows a significantly improved dissolution rate in comparison with free CA. Comparison of the pharmacokinetics between CA-beta-CD inclusion complex and free CA was performed in rats. The in vivo results show that CA-beta-CD inclusion complex has earlier t(max), higher C(max), and higher bioavailability than free CA after oral dosing. By comparing the AUC(0-t) of CA and CA-beta-CD inclusion complex, the relative bioavailability of CA-beta-CD inclusion complex to free CA was 506.3%, which highlighted the evidence of significantly improved bioavailability of formulation of CA with beta-CD. Thus, this beta-CD-based drug delivery system should be an effective oral dosage form to improve oral bioavailability of CA. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1557-1562, 2012