RESUMEN
This review concerns the definitions and appropriate analytical characterisations of herbal reference standards within the framework of regulatory requirements. It describes currently applicable rules and regulations, as well as future issues relating to the European Pharmacopoeia and United States Pharmacopoeia. It provides an update on the use and availability of pharmacopoeial (EP and USP) herbal reference standards since our last review was published in 2009. The continuing challenges facing manufacturers, suppliers and analysts are discussed on the basis of exemplary reference substances for herbal products in medicinal and food products. The article also reviews the special aspects of Brazilian stipulations (Brazilian Pharmacopoeia, Anvisa) by comparison with European regulations. The term herbal products as used throughout this article refers to herbal drugs, herbal preparations and finished herbal medicinal products unless a different meaning is obvious from the context. More specific terms are used where necessary.