When is it to late to take an emergency contraceptive?

After 5 days: The "morning after pil" works if started up to 5 days (120 hours) after unprotected sex. The sooner it is taken the more effictive it is. When started in the first 3 days (72 hours) it is about 90% effective. After 3 days, it still may work - but the failure rate is higher.

120 hours: They are most effective the sooner you take them; they are very good up to 72 hours. They still have some effectiveness up to 120 hours, and won't do any harm, so it's still worth a shot.