Cilest tablets are a type of hormonal contraception commonly known as 'the pill' or combined oral contraceptive pill. Cilest tablets contain two active ingredients, ethinylestradiol and norgestimate. These are synthetic versions of the naturally occurring female sex hormones, oestrogen and progesterone. Ethinylestradiol (previously spelt ethinyloestradiol in the UK) is a synthetic version of oestrogen and norgestimate is a synthetic form of progesterone. The daily dose of hormones taken in the pill work mainly by tricking your body into thinking that ovulation has already happened. This prevents an egg from ripening and being released from the ovaries each month. The contraceptive pill results in lighter, less painful and more regular menstrual bleeding. This means it is sometimes prescribed for women who have problems with particularly heavy, painful or irregular periods.