Absolutely everyone has, or still does this. Turns out it’s not that good an idea.
It’s a medical myth that you should put hydrogen peroxide on your wounds. Emergency room physician Dr. Michael Daignault writes, “Unfortunately, this deeply held belief extends across multiple cultures and generations. […] The underlying inaccurate consensus seems to be that the level of fizz generated equates to how well the wound is cleaned.” He notes that while hydrogen peroxide does have known antiseptic properties, it may do more harm than good when it comes to wound care. The issue is that while hydrogen peroxide can help clean, it doesn’t know the difference between bacteria cells and your own cells that are helping to heal your wound. So instead of helping, you could actually be causing corrosive tissue damage by applying it to your wounds, impairing the healing process, and you could even be irreversibly worsening the scarring process. The take-home message: you shouldn’t clean wounds with hydrogen peroxide or other caustic first aid antiseptics such as rubbing alcohol—instead stick to using clean water to gently rinse your wound, and then apply a small amount of triple-antibiotic cream and cover it with a clean dressing for smaller cuts and scrapes. Seek medical attention for larger wounds.
(Yahoo)