In the last 50 years science has provided new perspectives on the ancient art of herbal medicine. The present article discusses ways in which the evidence base for the professional use of 'Western' herbal medicine, as therapy to treat disease, known as phytotherapy, can be strengthened and developed. The evidence base for phytotherapy is small and lags behind that for the nutritional sciences, mainly because phytochemicals are ingested as complex mixtures that are incompletely characterised and have only relatively recently been subject to scientific scrutiny. While some methodologies developed for the nutritional sciences can inform phytotherapy research, opportunities for observational studies are more limited, although greater use could be made of patient case notes. Randomised clinical trials of single-herb interventions are relatively easy to undertake and increasing numbers of such studies are being published. Indeed, enough data are available on three herbs (ginkgo (Ginkgo biloba), St John's wort (Hypericum perforatum) and saw palmetto (Serenoa repens)) for meta-analyses to have been undertaken. However, phytotherapy is holistic therapy, using lifestyle advice, nutrition and individually-prescribed mixtures of herbs aimed at reinstating homeostasis. While clinical experience shows that this approach is applicable to a wide range of conditions, including chronic disease, evidence of its efficacy is scarce. Strategies for investigating the full holistic approach of phytotherapy and its main elements are discussed and illustrated through the author's studies at the University of Reading.

A brief discussion of the history of the use of herbal medicines from prehistoric times to the mid-twentieth century precedes an explanation of why usage of such remedies in the United States declined in the 1940s but returned to popularity in the 1980s. The provisions of the Dietary Supplement Health and Education Act of 1994 are presented together with its perceived influence, both positive and negative, on the health of the American people. Possible futures of herbal medicines are considered. The negative viewpoint that they will ultimately be rejected is refuted, and the more optimistic prediction that herbs are ultimately destined to become a part of mainstream medicine is defended. Stumbling blocks to such acceptance are evaluated and methods of overcoming them suggested. The urgent need for the development of a sensible regulatory environment encouraging the approval of botanicals as drugs is emphasized. After predicting a bright future for rational phytomedicines, the author opines that many of them will eventually play significant roles in medicinal practice.