I've used plan b twice in the last 5 days. is that dangerous?

No harm done but...: It won't hurt you to use plan b twice in 5 days; however, it may not prevent pregnancy to use it in this way. Plan b works by delaying ovulation. There is a limit to how often you can successfully delay ovulation in any given month. A second round may not be effective to prevent pregnancy for a second episode of intercourse. If you need it often, you might consider regular birth control.