So the question is asked, how does forgiveness heal? When you have resentment or grievence or you're feeling hostility towards anyone. Or for that matter if you have any of the other toxic emotions: guilt, shame, depression or fear. these.. er.. create the release of hormones such as adrenaline and coritsol, which effect bothe the cardiovascial system and also the immune system. You become immuno-comprimised and even your plattelets get jittery with high levels of adrenaline/ and they start the clotting cascade which could be cardiovascular illness heart attacks and storkes on the other hand when you forgive. which is letting go of the burden of judgement. then everything settles down. The hormones that are associated with those stressful responses, they settle down. their is now evidence that you release other kinds of neuro transmitters which are immuno .. and you're body starts to return to homestatis, Homeostatis is self regulation. and self healing. So the return to the self which beyond and the self which is the place forgiveness. and remember forgiveness is just letting go of the burden of judgemnet. then you're body returns to homeostasys the dynamic state