High Quality Content by WIKIPEDIA articles! Coniine is a poisonous alkaloid found in poison hemlock (Conium maculatum) and the yellow pitcher plant (Sarracenia flava), and contributes to hemlock`s fetid smell. It is a neurotoxin which disrupts the peripheral nervous system. It is toxic to humans and all classes of livestock; less than 0.2g is fatal to humans, with death caused by respiratory paralysis. Socrates was put to death by means of this poison in 399 BC. Coniine has two stereoisomers: (S)-(+)-coniine, and (R)-(-)-coniine, both of which are present in hemlock (see "Modern Chemical Studies", below). Coniine was first synthesized by Albert Ladenburg in 1886; it was the first of the alkaloids to be synthesized.