Ayahuasca brews vary widely in composition, depending on who brews it.

I'd be very wary of some self-styled shaman adding datura or some other nightshade plant to the brew (which is not unheard of), and that's something I definitely want to stay far, far away from.

Unless I was brewing it myself I'd want nothing to do with it either, because I couldn't be sure of what I was getting.