In ancient times, small doses of the plant were used to relieve pain, with a great risk of poisoning. One species, Conium maculatum, was used to carry out the death sentence in ancient times. The Greek philosopher Socrates was condemned to death in 329 B.C.E.; he killed himself by drinking a potion made from hemlock. The hemlock plant was introduced to North America from Europe, and has often been mistaken for a pretty garden plant. All parts of the weedy hemlock plant are poisonous, especially leaves and seeds. Hemlock is a member of the wild carrot family, and it grows along roadsides and waterways in North America.