Fly mushroom (Amanita muscaria) contains the neurotoxin
muscarine which makes it poisonous. The infusions of the 
mushroom are used as intoxicating drink in Siberia. Muscarine 
was first isolated in 1869. Topical application causes miosis, 
ciliary muscle contraction and lacrimation. Ophthalmic use of 
muscarine never becomes popular because of the difficulty of 
isolating the alkaloid in it pure form and also the highly toxic 
systemic effects.