The morning-after pill, also known as emergency contraception, is a medication that can prevent pregnancy if taken within a certain time frame after unprotected sex. It is available over-the-counter in the United States and many other countries, and it can be purchased at pharmacies, grocery stores, and online retailers.
The morning-after pill is most effective when taken within 72 hours of unprotected sex, but it can still be effective if taken up to 120 hours (5 days) after sex. It works by delaying or preventing ovulation, which is the release of an egg from the ovary. If no egg is released, then pregnancy cannot occur.