A simple and selective high-performance liquid chromatographic technique was developed for the determination of taxol in mouse plasma. This technique employs a single extraction step followed by isocratic chromatography on a C18 analytical column and ultraviolet detection at 227 nm, and is suitable for the analysis of microsamples (50 microliters plasma). A series of aromatic and aliphatic benzamides were synthesized as internal standards; N-octylbenzamide was evaluated most extensively. The calibration curve is linear within the range 0.15-10 nmol/ml. The intra-day and inter-day coefficients of variation were below 7%. The specificity of the assay was confirmed by comparing the chromatographic properties of samples with authentic taxol, using a diode-array detector. The assay was used to conduct pharmacokinetic studies of taxol in mice after administration in different formulations.