"Worst thing you can do to your body"
Well I suppose cutting into the body to adjust organs might be worse- or surgery as we call it.
Chemotherapy I hear is quite hard on the body.
Setting a bone hurts like hell.
Lots of the things medical doctors do to us are not pleasant at the time and can be "hard on the body" but that doesnt mean they shouldnt be done. Blood transfusions have proven to be life saving. So much so that there is a global industry built around the harvesting and preservation of blood. Hospitals keep stores of blood like they keep stores of scalpels, antibiotics and bandaids. Blood is a vital part of our modern, medical apparatus and it works. Will there be a better alternative in the future? Possibly. As former and current JW's its only our cult training that makes us think longer about blood than about x-rays or MRIs or beta-blockers or any other form of modern medical treatment.