Butterbur (Petasites) is an ancient plant which has been used for medical and edible purposes with its spasmolytic agents. However, toxic alkaloid content of the plant limits its direct usage. The paper covers the pyrrolizidine alkaloids (PAs) and butterbur themes in detail in order to display the outline of alkaloid-free plant extract production for medical and edible purposes. The toxic PAs and medicinal constituents of the plant are described with emphasis on analytics, physiological effects and published patent data on alkaloid free extract production. The analytics is based on several commonly used analytical methods including liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry and enzyme linked immunoassay analysis of PAs and N-oxides based on published literature data of butterbur. The analyses of major medicinal constituents of butterbur are given and the physiological effects of these compounds have been discussed to attract attention to the importance of alkaloid-free extract production. The concentration distributions of the medicinal constituents and toxic PAs in different parts of the plant and the outcomes of the published patent data provide comprehensive information for proper plant raw-material selection and production of alkaloid-free butterbur extracts. The review is intended to guide researchers interested in medical plant extracts by providing comprehensive data on the medical plant butterbur and its chemical constituents. (C) 2012 Elsevier B.V. All rights reserved.