I was bitten by a big black snake once. It was my fault as I decided to goof with him. When their threatened like that they can get real agressive so I found out.
He whacked me right on the shin and about flipped me. I never realized they hit that hard when they strike. Kinda like someone giving you a charley horse. Anyway, it swelled up like a balloon and turned all kinds of colors and it did make me sick for a day, nothing terrible, but kinda woosey.
He was about 6ft long. Thank goodness it was only a black snake.