Published July 27, 1990.
List of German Commission E Monographs (Phytotherapy)
Petasitidis hybridus, petasites.
Petasitidis folium, petasites leaf.
Petasites consists of the whole plant of Petasites species [Fam. Asteraceae], as well as preparations thereof.
Petasites leaf consists of the leaves of Petasites species, as well as preparations thereof.
Petasites leaf or its preparations are used for nervous cramp-like states and such states associated with pain, colic, headaches, and to stimulate the appetite. Combined with other herbs petasites is used for complaints and disorders of the respiratory tract, chills, for liver, bile, and pancreas disorders, to strengthen the nerves, promote sleep, and to prevent internal restlessness.
The effectiveness for the claimed uses is not documented.
Petasites contains in all plant parts greatly varying amounts of toxic pyrrolizidine alkaloids (PA), which are known to damage organs, especially the liver. In animal experiments, PA have been shown to have carcinogenic effects brought about by a genotoxic mechanism.
In consideration of the risks, and lack of documentation for the effectiveness of the herb for the claimed applications, a therapeutic application cannot be justified.