They work, I've done em. They used to be pretty popular in the days of Ken Kesey and his Merry Pranksters too, so they're not without some merit.

I personally threw up early on because I didn't do anything smart like wash them or grind em up, and they taste pretty nasty. But I was definitely feeling effects. My pupils were very big, and I was kind of.. confused. I got like a threshold dose, I think, cause I barfed up a big clump of seeds very early, like I said.

No matter what precautions you take, I'd recommend you take a shot or two of Pepto Bismol before you down em. Just so you don't waste the trip.