Over the past 30 years, the National Cancer Institute has been involved in the preclinical and/or clinical evaluation of the majority of those agents approved for the treatment of cancer. Many of the new agents under consideration in the NCI program are either natural products or derivatives of natural product leads, and of critical importance to their development is the issue of drug supply. In responding to the drug supply crisis which emerged with the demonstration of the clinical efficacy of taxol, the NCI has identified several important lessons for those interested in natural product drug discovery and development. As a result, the NCI has developed plans to avert similar supply crisis in the future by initiating exploratory research projects for large-scale production of promising agents at the earliest possible point following the demonstration of confirmed antitumor activity. These plans, together with a review of the development of taxol, are presented in this paper.