Diane-35 tablets contain two active ingredients, cyproterone acetate and ethinylestradiol. This combination of medicines is also known as co-cyprindiol.This medicine is also an effective combined oral contraceptive pill. Cyproterone acetate is a progestogen derivative, and the other ingredient, ethinylestradiol, is a synthetic version of the naturally-occurring female hormone, oestrogen. The medicine works as a contraceptive by preventing the ripening and release of eggs from the ovaries, as well as increasing the thickness of the cervical mucus, which makes it more difficult for sperm to cross from the vagina into the womb. It also changes the lining of the womb so that it is less suitable for any fertilised eggs to successfully implant in.