I read an account of a guy that went on a psychodelic tourist trip to the Amazon, went through the ritual with a bucket for vomit on his side and had a massive reaction to it. For the next six months he could not read anything in print nor on computer screens.
That's the problem: he went on a psychedelic tourist trip. Nobody on my trip was there for fun: we were there to heal.
Ayahuasca is absolutely
NOT a recreational drug. Mushrooms can be recreational in lower doses, a waste of such a divine gift as it may be, but all psychedelics are powerful tools that should be treated with reverence, as you would revere the holy communion if you were a Catholic.
If you approach Mother Ayahuasca with utmost respect, adhere to the dieta, and absolutely abstain from SSRIs for months before, you will most likely have a positive experience. Ayahuasca is non-neurotoxic, in fact it as well as psilocybin mushrooms can encourage neurogenesis.
Typically the shamans make less potent brews to see how people react -- with the popularity of ayahuasca in recent years, they don't want to get a bad reputation. On my journey, the first two nights of aya were mostly useless to me, but on the third night he significantly increased the dose of DMT -- and I increased the dose I asked for -- and I had one of the most mystical and wonderful experiences of my life.
I wouldn't fear ayahuasca, but again I wouldn't go back to her unless I felt the need, like with you and LSD. People feel the "call" to her. If someone goes just for fun, or without reverence, they could be in for a terrible experience.
Back to the point of the thread: it could help you with IBD. Most likely it won't hurt.