Because the i-pill is an emergency contraceptive, it is recommended that you take it as soon as possible after an unprotected sexual encounter to avoid unwanted pregnancy. It's best if you take the pill within 72 hours (three days) of having unprotected intercourse. It can, however, be used for up to 5 days in some situations (particularly if a doctor recommends it). However, keep in mind that the sooner you start using the pill, the better your chances of contraception.