100 milliamps, trans-thorasically is enough to stop the heart. That said, there are uses for electric current, applied to the body, that can be helpful. T.E.N.S. (Trancutanious Electrical Nerve Stimulation) has been used for decades to relieve pain, and to fight swelling. I have one myself, and use it when I need to.
However, this post is 100% right, electricity must be treated with respect, and caution is a must. I work on high voltage system often, and if care is exercised, electricity is a good servant, but it is a poor master!