It really depends on what you mean by work... Amanitas are considered a deliriant, and the effects range from pleasant to unpleasant. I have a website which gives some information about them: Amanita Muscaria Information More commonly though, people are referring to psilocybin mushrooms, which are much different, and generally more powerful.
When I did them they didn't really do jack shit too me, and I ate like 1/4oz of them. I got 1 hallucination, and felt nothing really. Waste of money imo.