Physicians are increasingly recommending the use of plant-derived products, partly because of a growing dissatisfaction among consumers with conventional medicines, but also because of the progress made in the chemical, pharmacological and clinical study of herbal medicinal products, the use of innovative galenical forms and the growing importance of self medication. Quality is a key issue in the development of herbal medicinal products that have consistent safety and efficacy, and quality can only be achieved if it is prioritized from the earliest stages of the development process. Problems in the development of herbal remedies include the frequent lack of standardized products (leading to a poor reproducibility of results and lack of batch-to-batch uniformity), a lack of toxicology, pharmacokinetic and pharmacodynamic data, as well as of dose-response and interaction studies. In addition, the placebo effect in trials with herbal remedies is often very high. Research involving herbal medicinal products must progress from the use of traditional evidence and/or open, observational trials to randomized, double-blind, placebo-controlled trials, the 'gold standard' of clinical and scientific research. Over time, the development process for herbal medicinal products should become more closely aligned with the development of new chemical entities. Pharmacovigilance is also slowly becoming a standard tool to monitor the safety of herbal medicinal products. Yet we should not discard the legacy of traditional wisdom because ethnopharmacology and knowledge provided by existing clinical trials (be they open, observational studies or small, double-blind investigations) is a source of invaluable insight into the safety and efficacy of herbal remedies. Ideally, a registration dossier for any herbal medicinal product should include both the results of appropriate preclinical and clinical studies, and the wealth of knowledge that has accumulated from the traditional use of the product.