Current perspectives on herb-drug interactions in the European regulatory landscape.

Herb-drug interactions have turned out not to be a major issue in the European regulatory landscape. For a minority of herbal preparations, herb-drug interactions are clinically relevant, e.g., between high-dose St.John's wort extracts and a number of chemical substances. The inclusion of adequate information on such interactions into the package leaflet is important for the safe use of the products. Information on potential interactions is also part of the official HMPC monographs. However, only for some herbal preparations described in these monographs, such a potential is known. Thus, in accordance with the relevant European guidance documents, potential interactions should be assessed critically for their clinical relevance, and a balanced assessment is required when regulatory documents are established or regulatory measures are implemented.