Because use of herbal remedies is increasing, a risk–benefit profile of commonly used herbs is needed. This article provides a clinically oriented overview of the efficacy and safety of ginkgo, St. John's wort, ginseng, echinacea, saw palmetto, and kava. Wherever possible, assessments are based on systematic reviews of randomized clinical trials. Encouraging data support the efficacy of some of these popular herbal medicinal products, and the potential for doing good seems greater than that for doing harm. The published evidence suggests that ginkgo is of questionable use for memory loss and tinnitus but has some effect on dementia and intermittent claudication. St. John's wort is efficacious for mild to moderate depression, but serious concerns exist about its interactions with several conventional drugs. Well-conducted clinical trials do not support the efficacy of ginseng to treat any condition. Echinacea may be helpful in the treatment or prevention of upper respiratory tract infections, but trial data are not fully convincing. Saw palmetto has been shown in short-term trials to be efficacious in reducing the symptoms of benign prostatic hyperplasia. Kava is an efficacious short-term treatment for anxiety. None of these herbal medicines is free of adverse effects. Because the evidence is incomplete, risk–benefit assessments are not completely reliable, and much knowledge is still lacking.

Aims  The aim of this systematic review was to assess the published clinical evidence on interactions between herbal and conventional drugs.Methods  Four electronic databases were searched for case reports, case series or clinical trials of such interactions. The data were extracted and validated using a scoring system for interaction probability.Results  One hundred and eight cases of suspected interactions were found. 68.5% were classified as ‘unable to be evaluated’, 13% as ‘well‐documented’ and 18.5% as ‘possible’ interactions. Warfarin was the most common drug (18 cases) and St John's wort the most common herb (54 cases) involved.Conclusion  Herb–drug interactions undoubtedly do occur and may put individuals at risk. However our present knowledge is incomplete and more research is urgently needed.

Homeopathy remains one of the most controversial subjects in therapeutics. This article is an attempt to clarify its effectiveness based on recent systematic reviews. Electronic databases were searched for systematic reviews/meta‐analysis on the subject. Seventeen articles fulfilled the inclusion/exclusion criteria. Six of them related to re‐analyses of one landmark meta‐analysis. Collectively they implied that the overall positive result of this meta‐analysis is not supported by a critical analysis of the data. Eleven independent systematic reviews were located. Collectively they failed to provide strong evidence in favour of homeopathy. In particular, there was no condition which responds convincingly better to homeopathic treatment than to placebo or other control interventions. Similarly, there was no homeopathic remedy that was demonstrated to yield clinical effects that are convincingly different from placebo. It is concluded that the best clinical evidence for homeopathy available to date does not warrant positive recommendations for its use in clinical practice.