Opill is a progestin-only daily oral contraceptive (birth control pill) thats safe and effective when used as directed to help prevent pregnancy. Its the only over-the-counter birth control pill available in the United States. Opill helps prevent pregnancy in women and people who can become pregnant. Its not an emergency contraceptive (morning after pill) and wont prevent pregnancy when used after unprotected sex. It also doesn't protect against HIV/AIDS or other sexually transmitted diseases (STDs). 1 month pack.