Vysorel/Isorel is an aqueous extract from fresh mistletoe (viscum album). A number of components with different possible effects have been isolated, but exact analyses of the preparation have not been published. One ampoule 'Stärke 60' of 1 ml contains the extract of 60 mg mistletoe. Vysorel/Isorel is recommended in all malignant diseases, in 'precancerous' conditions and for prevention of relapse. Vysorel/Isorel is supposed to be taken subcutaneously according to a rhythmic schedule. Drug costs for one year in precancerous conditions are approximately 900 DM, for prevention of recurrence approximately 1800 DM, in the case of inoperable tumour approximately 3800 DM. Vysorel/Isorel is also a product of the anthroposophical medicine according to R. Steiner. It is marketed by Novipharm GmbH as Isorel in Austria and as Vysorel in the Federal Republic of Germany. The clinical efficacy of Vysorel/Isorel is derived from the demonstration of proteins from mistletoe (so-called 'Vester's Protein') with cancerostatic activity in vitro. No preclinical or clinical investigations are available. None of the 33 case histories suggests that Vysorel/Isorel is effective in the treatment of malignant diseases. Vysorel/Isorel is not registered in Switzerland at the IKS. It has been permitted in Austria since 1983 and in Germany since 1986.