Killer Weed!

[Blktail]

Current through the heart is what kills you. Voltage is what pushes the current through you.
Less than 5 milli-amps through your heart will not generally harm you.
5 to 50 milli-amps will make your heart try to beat at 120 beats per second. This destroys the heart muscle.
More than 50 milli-amps throught the heart will make the muscle clamp down solid and stop. If you are lucky, it will start again when you hit the floor.
At some point the current going through you will heat up the tissue and burn you. This amount of current requires a great amount of voltage to push it.
Generally speaking, 120 volts will not kill you outside of the bathtub.
240-600 volts may kill you or hurt affected muscles. They may even pull themselves from the bone when they contract violently.
Primary voltages of 10,000 volts and up tend to cause terrible burns, especially along blood vessels and nerves.

So much for electricity 101.