Capsaicin was administered in a semisynthetic powdered diet at 0.03125% level for the lifespan of Swiss mice starting from 6 weeks of age. As a result of C treatment, tumors of the cecum were induced in 22% of females and 14% of males, whereas the corresponding tumor incidences in untreated female and male controls were both 8%. Histopathologically, the tumors were classified as benign polypoid adenomas. Capsaicin is the main pungent principle of hot pepper, which is consumed in high quantities by humans worldwide. The capsaicin content of some chili varieties ranges up to 0.53%.