Always thought I'd like to to an ayahuasca retreat one day...But not anymore. I have a friend who totally went off the deep end.
You're supposed to go in with a clean mind and body...de-toxed and ready for anything. My friend did not. He was on vacation, drank before it, drank after it. Galloped around europe for 2 weeks before getting kicked off his plane home...spent a time in a London psychiatric ward before getting cleared to come home. Still hasn't recovered. He was always a bit eccentric...but for a few weeks spoke in an english accent and was just not all there. Still isn't. It's been almost 6 months and he's living with his parents, seeing a shrink and is overall not the same.
This is one situation...he didn't treat the trip with the respect and dedication it takes to make it worthwhile. If you do decide to take ayahuasca...just be sure you are running with a clean mind and body. No pot, alcohol or any mind altering substances for a few weeks beforehand...and certainly afterwards. I can't stress this enough. You don't want to be the guy in a room that in your own mind is "enlightened" and seeing things clear as day...only to have everyone else think you're a loon. Again...this is one person and my only insight into the drug. But it has made me think twice about it. Mescaline on the other hand....I highly recommend. Felt like I was on Pandora. I could see the trees breathing