Neoplasms of the forestomach in mice ingesting dihydrosafrole

The maximal tolerated doses of dihydrosafrole, safrole, and isosafrole were given by continuous oral administration, starting at the age of 7 days, to both sexes of two hybrid strains of mice - (C57BL/6 X C3HAnf)F1 and (C57BL/6 X AKR)F1. Hyperplasia and carcinomas of the forestomach were significantly increased in female mice of both strains and in male mice of the latter strain ingesting dihydrosafrole. By contrast, neoplasms of the forestomach were not increased in mice receiving safrole or isosafrole. Mice with neoplasms of the stomach generally did not have neoplasms of the liver.