Is It O.k. to Use Hydrogen Peroxide on an Open Wound?

If there is fibrin in the wound (early, healing tissue), then 1-2 times of cleaning the wound with hydrogen peroxide is okay, in order to lift some of the fibrin off of the healing wound (debridement). In general, any more use of this than that is not recommended, as hydrogen peroxide is known to slow the progression of healing, if used in excess. This is likely why you received two seemingly conflicting pieces of information, when in essence, both of your physicians are right.

I generally advise my patients not to use hydrogen peroxide in an open wound as it is toxic to the newly healing cells and it will increase the healing time.  It is fine to use as a surface cleanser to loosen crusted blood and debris from a closed or sutured wound. 

It is safe to use hydrogen peroxide, yes, but it will sting. So I recommend people clean wounds with 1/2 water and 1/2 hydrogen peroxide, as it cuts down on the stinging and still helps to clean the area.

"This answer has been solicited without seeing this patient and cannot be held as true medical advice, but only opinion. Seek in-person treatment with a trained medical professional for appropriate care."