When should you take the emergency contraceptive  or morning after pill?

Within 72 hours. Emergency contraception or the "morning after pill" should be taken within 72 hours of unprotected intercourse.

Related Questions

What are some advantages of the emergency contraceptive or morning after pill?

Many advantages. Emergency contraception is a highly effective method to prevent unintended pregnancies. It can be used up to 5 days after an episode of unprotected intercourse i.e., contraceptive failure, sexual assault, exposure to a drug that can cause birth defects. Planb is acessible over-the-counter for women age 18 and older.
The major advantage. Is that it can be used after -the-fact if there is an episode of failed birth control.

What is the emergency contraceptive? Is it the same as a morning after pill?

Yes. Emergency contraception is available as a 'morning after' pill. There are other forms as well. The morning after pill is available at your local pharmacy and is quite effective if taken in the first 48 hours after unprotected intercourse.

If the emergency contraceptive or morning after pill doesn't prevent pregnancy?

See your doctor. Emergency contraception is an option to prevent unintended pregnancy. It is available through a pharmacy, and doesn't require a prescription if you are over 18 years old. If you take this medication and a pregnancy is not prevented, you should see your healthcare provider. Ec doesn't harm a developing pregnancy, but you will want to discuss all of your options for the pregnancy.
Morning after. Morning after pill doesn't prevent pregnancy 100%, you still have about 27% chance to get pregnant.