Within hw much hours does an ecp works whn taken within an hour aftr unprctd sex?is it necesry to take an ecp after a meal? whn is it adviced to take?

Take within 72hrs: Assuming that you're referring to emergency contraceptive pills, given the context of your question, they're most effective when taken within 72 hours of unprotected sex (best as soon as possible w/repeat if vomiting less than 3yrs later). However, they only protect against pregnancy, not sexually transmitted diseases. Follow directions for your particular brand. Your pharmacist & PP can be help.