are amanita muscaria poisonous? if so, how much?

Yes. Usually, they just make you sick.

But the "how much" is hard to answer. It's used as a hallucinagen, and not quite like the kind that liquify your liver and kill you in a few days, but still...it is mildly poisonous, which is why some people play with it for "fun". Keep in mind, if you're one of those type that are looking for drug experiences - if you don't like your experience....you're stuck with it for about 12 hours. Something to consider.

They are not poisonous if you par boil them for 15 minutes and tip the water away containing the toxins. They are eaten this way in some countries in America, Europe and Asia.

They are hallucinogenic and poisonous if eaten raw but there is only one recorded case of possible death in the 1880's.