Lack of prevention of large intestinal cancer by VPS, an extract of Coriolus versicolor mushroom.

Cancer prevention studies were conducted with VPS, a hot water extract of the Coriolus versicolor (CV) mushroom, in female Swiss mice. The extract was administered in the diet for life to the animals. Three groups of mice received the following treatments: a). 1,2-dimethylhydrazine dihydrochloride (1,2-DMH) was administered as 10 weekly subcutaneous injections of 20 microg/g body weight, starting at 9 weeks of age; b). VPS was given at a 2% dose level starting at 7 weeks of age followed by 1,2-DMH, as described in group a; c). 1,2-DMH was administered as described in group a followed by VPS at a 2% dose level starting at 21 weeks of age. The number of animals with large intestinal tumors and the total number of these tumors were: a). 30,321; b). 29,359; and c). 28,415. These differences are not statistically significant. Because extracts of the CV mushroom are used by cancer patients as nutritional supplements in the U.S., and particularly in the Orient, the present negative result should caution its users.