Question: how long does it take for plan b to work after you take it?
Answer: How does the plan B® morning-after pill work? plan B® comes in a one-pill dose. If taken within 72 hours (3 days) and preferably within 12 hours after a contraceptive accident or unprotected sex, it can prevent pregnancy by doing one of three things: Temporarily stops the release of an egg from the ovary.