The combined oral contraceptive pill is usually just called the pill.
It contains synthetic (artificial) versions of the female hormones oestrogen and progesterone, which women produce naturally in their ovaries.
The pill is usually taken to prevent pregnancy, but can also be used to treat:
When taken correctly, the pill is over 99% effective at preventing pregnancy. This means that less than 1 in 100 women who take the pill will get pregnant in a year.
Who can take it?
Not all women can take the pill. For example, you should not take it if you are pregnant, or if you smoke and are aged 35 or older.
Learn more in special considerations for the combined contraceptive pill.
How the pill works
Getting pregnant happens when a man's sperm fertilises a woman's egg.
The pill prevents the ovaries from releasing an egg each month (ovulation). It also:
The pill can be started on any day of your menstrual cycle. There is special guidance if you have just had a baby, a miscarriage, or an abortion.
Learn more in how to take the combined contraceptive pill.
Types of combined pill
Although there are many different brands of pill, there are three main types:
It's important to take the pills as instructed, as missing pills, or taking them at the same time as certain medicines may make them less effective. Read more about what to do if you miss a pill and the pill - interactions.
Risks and side effects
There are risks associated with using the combined contraceptive pill, such as blood clots, although they are not common. For most women, the benefits of the pill far outweigh the risks.
Side effects are also uncommon, but can include: