Plan B One-Step® is your backup plan—emergency contraception in just one pill. The sooner you take it, the better it works. When taken as directed—within 72 hours (3 days) after contraceptive failure or unprotected sex—approximately 7 out of 8 women who would have gotten pregnant will not become pregnant after taking Plan B One-Step®.

Plan B One-Step® is safe, effective, and FDA-approved. It contains levonorgestrel, the same ingredient found in many birth control pills. The difference is that Plan B One-Step® requires just one pill, which uses a larger dose of levonorgestrel than a single birth control pill. And, unlike many birth control pills, Plan B One-Step® doesn’t contain any estrogen, only progestin.

Plan B One-Step® is not RU-486 (the abortion pill)—it won’t work if you’re already pregnant, and it won’t affect an existing pregnancy.

Plan B One-Step® is an effective backup plan, but it isn’t regular birth control and should not be used that way. It’s not as effective as other methods of birth control used consistently and correctly, so it’s important to have another reliable source of birth control that’s right for you. It won’t protect you from HIV infection (the virus that causes AIDS) or any other sexually transmitted diseases (STDs).