Effect of ethynodiol diacetate with ethinyl estradiol on the mammary glands of rhesus monkeys: a preliminary report.

The oral contraceptive combination of ethynodiol diacetate with ethinyl estradiol (Demulen) was given cyclically to 48 female rhesus monkeys for 5 years. Doses employed were 1, 10, and 50 times the human dose. Treatment did not induce palpable breast nodules, and there were no deaths from mammary gland cancer.