Rhubarb use in patients treated with Kampo medicines--a risk for gastric cancer?

In vitro mutagenic effects have been reported for ingredients contained in rhubarb. Therefore, rhubarb (Rhei Rhizoma) as an anthranoid laxative could be associated with a risk of developing gastric cancer as well as colorectal cancer. We are not aware of any reports that have examined the relationship between the use of rhubarb and the development of gastric cancer. During the period between 1979 and 1999, we treated 14,616 patients using various Kampo medicines, which sometimes contained rhubarb. In the present study, we determined whether patients, diagnosed with gastric cancer during the period between 1979 and 1999, had been administered rhubarb before the development of gastric cancer. Among the 10 enrolled patients, only 2 patients had been administered rhubarb before the development of gastric carcinoma. The other 8 patients had never received rhubarb before the development of gastric carcinoma. Rhubarb use may have little connection with the development of gastric cancer in practice, even if some ingredients in rhubarb have shown carcinogenic activity in experimental studies.