A few months ago I took my roommate into the ER. Turned out he had gullbladder stones.

They kept in the hospital for five or six days to monitor to him to see if it passed or if surgery would be needed. They also wouldn't let him eat or drink ANYTHING for the first few days he was there. He got to sip some water or something at the end of the third day there.

It eventually passed, but I know it wasn't his first time he got them (just always passed w/o going to the ER) and he's had issues since.

Dave