Yes you can od on water. In fact there was a water drinking contest in the news about a month ago where the winner, a woman, died from water intoxication. Too much of anything is bad for your body. Think about it, you rbody has to work to get anything out of it. You can also kill your liver with significant doses of THC. Nothing is going to happen if you just smoke responsibly though.

As far as marinol, it is synthetic THC. It comes in little round capsules smaller than a pea. They are black or very dark purple in color and contain an oil on the inside (they are gel caps much like a vitamin E cap.). Take 10, as one poster suggested he was thinking of doing, and you WILL cause permanent liver damage. Come on people, don't be greedy. Anyway, these things are ultra expensive because they cost so much to make. I think one pill is like $30 or something. They are used for cancer patients to help control severe nausea after chemo. They also are prescribed to AIDS patients to boost appeptite.