Suspension cultures of Taxus cuspidata were grown in shake flasks and Wilson-type reactors where bubbled air provided both agitation and mixing. Taxol titers of 22 mg l(-1) were achieved for both configurations in 20 days for a volumetric productivity of 1.1 mg l(-1) day(-1). This productivity is many-fold higher than reported for other Taxus sp. suspension cultures. Taxol was released to the extracellular medium as it was produced with little intracellular retention (less than or equal to 10%). Taxol production occurred during the last seven days of the cultivation period and was not growth-associated. Although the same taxol titers could be obtained in both reactor types, nutrient uptake rates were faster in the Wilson-type reactor than in shake flasks. Formation of a growth ring in the Wilson-type reactor reduced measured cell mass yields.