If you think Jehovah Witnesses are a bit extreme about the blood transfusion issue, Christian Scientist don't believe in any type of medical intervention and believe illnesses are the result of fear, ignorance, or sin.
I have read some of the christian scientific magazines. I do not know if the magazine follows the same principal as the christian scientist but I hope not. I find that their belief of sickness as a kind of curse from god is a little over board. I do know that your faith in the lord above all other things can bring happiness and a well feeling to you. I know that having faith in god to help cure you of a problem is a known fact. I do know that my faith in god and my belief that My body is well is keeping me alive to this day. I know if I did not have faith I would have quit living long ago.
I do not believe that all illness is caused by fear, ignorance or sin. There is some things that even scientist can not understand. I believe my illnesses were caused by man not god.