The inclusion complex between the powerful antimalarial agent Artemisinin and beta-cyclodextrin has been studied by means of Circular Dichroism and elucidated by Density Functional Theory calculations on the isolated molecule combined to a statistical Monte Carlo search of the most stable geometry of the complex. The results evidence a host-guest structure in full agreement with the almost unaffected functionality of the drug, which is found to experience a significant hydrophilic environment when complexed. (C) 2003 Elsevier B.V. All rights reserved.