hrdrogen peroxide, H2O2, can be placed on open wounds as in an antiseptic. When you do this, bubbling occurs because

2H2O-------> 2H2O + O2
However, H2O2 only decomposes slowly in the bottle. Why does the wound accelerate its decompostion

I have observed this many times. My best guess is that tissue & blood catalyze the reaction. Another tutor may have a more authoritative answer .