Buffered aspirin has an added buffering agent so that it is easier on the stomach.
YES, don't ever give a baby regular adult aspirin its way to strong.
MgO is the buffering agent in Bufferin
In veterinary medicine, aspirin is avoided due to companion animals (ie, dogs and cats) being much more sensitive to the negative side effects.
Buffered aspirin helps coat the stomach so the stomach does not get upset.