Ionic liquid based, ultrasound-assisted extraction (ILUAE) was successfully applied to the extraction of 3 alkaloids, vindoline, catharanthine and vinblastine, from Catharanthus roseus. Twelve ionic liquids, with different cations and anions, were investigated in this work and [Amim]Br was selected as the optimal solvent. In addition, ultrasound extraction parameters, including soak time, solid-liquid ratio, ultrasound power and time, and the number of extraction cycles, were optimized. ILUAE offered short extraction times (from 0.5 h to 4 h) and remarkable efficiency. The use of ionic liquids, in the ultrasound-assisted extraction of key chemicals from medicinal plants therefore shows great potential. (C) 2011 Elsevier B.V. All rights reserved.