Fractional precipitation is a simple method for pre-purifying paclitaxel extracted from plant cell cultures. However, the fractional precipitation process has been inherently problematic due to the lengthy precipitation time (similar to 3 days) that is required. In this study, we evaluated the effect of crude extract purity and pure paclitaxel content on the behavior (purity, yield, fractional precipitation time, precipitate shape and size) of fractional precipitation to improve paclitaxel purification efficiency. As the crude extract purity and pure paclitaxel content were increased, the yield and purity of paclitaxel were increased and the precipitation time and precipitate size were decreased. Furthermore, we found that the maximum amount of pure paclitaxel content for fractional precipitation was 0.45-0.51% (w/v) regardless of the purity of crude extract. (C) 2012 Elsevier B.V. All rights reserved.