The Mexicans have used Chapparo Amargo for a long time. Most herbs are going to be safer to use as far as toxicity is concerned, although there can be situations that this may not be true. Research is always important.
As far as the psychotropic effects, this may have been due to herxheimer reactions and not the herb itself. I took this herb and noticed no such problems.
As a side note, I would purchase the extract (extracto) from the same place as the original poster.