Quote:
Lethal (toxic) doses of LSD are conservatively several tens of thousands of times as much as a normal dose, making it (in the toxic sense) one of the safest drugs known. See section on Pharmacology for description of bodily side-effects.
The LD50 for psilocybin (active ingredient in mushrooms) is 275 mg/kg i.v. in mice. Of course, it would take lots more p.o. to kill someone.
The reported LD50 values for LSD are 46, 16.5, 0.3 mg/kg I.V. for mice, rats, and rabbits, respectively. Again, it's hard to accurately translate these numbers to oral values.
Note that an average human dose is 0.001 mg/kg, ie, 1 microgram/kg, ie, 1 part per billion by weight.