What are the effects of shrooms, in terms of health?

Hard to say, mainly: because studies where "shrooms' are actually analyzed have shown that some of them have psilocybin and are 'genuine', while others have LSD or even PCP (phencylidine or angel dust) which can be very dangerous. Bad trips with psychosis and flashbacks have been reported, and dry mouth, blurred vision, urinary retention, and hyperthermia have also occurred. You don;t really know what you are getting.