In order to enhance the oral bioavailability, trans-resveratrol (t-RVT) nanoparticles were prepared by temperature-controlled antisolvent precipitation with the hydroxypropyl methylcellulose as the stabilizer. The mean particle size was reduced by decreasing the precipitation temperature, mainly due to the higher nucleation rate and slower growth rate. The freeze dried t-RVT nanoparticles were well reconstituted in aqueous solution maintaining a similar particle size and distribution in the nanosize range that is prior to freeze drying without the aid of cryoprotectants. The SEM images exhibited some aggregation of individual spherical nanosized particles. The FT-IR analysis confirmed that the molecular structure of t-RVT nanoparticles was not changed after the precipitation process. Furthermore, t-RVT nanoparticles showed significantly enhanced saturation solubility and dissolution rate by the decrease in particle size and degree of crystallinity when compared to the raw t-RVT. The combined results have demonstrated that this method can considerably enhance the bioavailability of t-RVT. (C) 2011 Elsevier Ltd. All rights reserved.