Kombucha, a fungal infusion, is a 'symbiotic mixture' of bacteria, yeasts, tea and sugar. A number of components are listed, but exact analyses are not published. On the basis of 'thorough detoxification', Kombucha is claimed to be a prophylactic and therapeutic agent in countless diseases, such as rheumatism, intestinal disorders, ageing and cancer. All 'stages of the Sklenar blood picture' have to be treated with Kombucha Drink, Kombucha Drops, coli preparations and Gelum oral-rd for a period of months. A litre-bottle costs 13 DM, the blood analysis 150 Sfr. In the 1960's Dr. R. Sklenar developed a 'biological cancer therapy with Kombucha as the main agent' and his own system of diagnosing cancer. Sklenar's diagnosis of cancer is based on iris diagnosis and demonstration of the causative organism by means of a 'Blood picture according to Dr. Sklenar'. He claims, on one hand, that cancer is only one of the many metabolic diseases and, on the other, that viruses, in his view parasitic microorganisms in general, are responsible for the pathogenesis of cancer. No preclinical and nor investigations are available, as 'success has proved him (Dr. Sklenar) to be right'. The seven 'case histories' described have no solid medical data. There is so far no evidence to support the claim that Kombucha offers 'effective biological treatment of cancer'.