ellaOne^® is the most effective morning after pill*. If you have had unprotected sex, taking ellaOne^® can prevent unplanned pregnancy. EllaOne Emergency Contraception Morning After Pill can be effective for up to 5 days (120 hours) after unprotected sex has taken place, but like all morning after pills it is more effective the sooner you take it. EllaOne Emergency Contraception Morning After Pill is intended for use in the case of emergency it is not meant to be a replacement for a regular method of contraception.