The contribution of plants to western medicine is briefly considered using alkaloids as examples of one class of pharmacologically active natural product. Plants and plant products are present in 14 of the 15 therapeutic categories of pharmaceutical preparations which are currently recommended to medical practitioners in the U.K. and they form an important part of our health-care system in the western world. There is considerable scope for new drug discovery from traditional medicines which are used throughout the world and some recent developments are commented upon and conclusions are made.