Distinct spatio-temporal variations of metal ions and Taxol production were observed for Taxus cuspidata cells immobilized on polyurethane foam. The Taxol content in the inner foam layer reached 215 mu g g(-1) at day 30, which was 40-fold higher than that in the outer foam layer, and the Ca2+ and Mg2+ contents were 5.3 and 3.7 times higher, while the K+ content was 5.5 times lower. Thus higher intracellular Ca2+ and Mg2+ contents and lower intracellular K+ content may favor the Taxol biosynthesis in immobilized Taxus cuspidata.