Took plan b after 4 days..will it be effective?

Less effective : The longer after unprotected sex you take it the less effective the Plan B is. 4 days out it still works, but not near as well as taking it the same day. But certainly better than nothing. If you can see a doctor tomorrow to get a copper iud it will work better than everything else.

Agree w Dr. Didrich: Plan B One-Step is up to 89 % effective when taken within 72 hours (3 days) after unprotected sex. It can reduce chance of pregnancy by up to 95% if used within 24 hours. It continues to reduce the risk of pregnancy up to 120 hours (5 days) after unprotected sex, but is less effective as time passes.