While most people harping on the "there are no known negative health effects." claim are talking about the drugs making people crazy I would point out that some psychedelics can also make people become sick. It passes, no long term harm, but it still seems like a miserable time and one I'd call a "negative health effect".

Sure, too much alcohol can cause people to get sick too, but then nobody ever said alcohol had "no known negative health effects" either.