What plant was used to execute Socrates and contains coniine?

The plant used to execute Socrates and containing coniine was poison hemlock, scientifically known as Conium maculatum. It is a highly poisonous flowering plant in the carrot family, Apiaceae, and its major toxic alkaloids include coniine and gamma-coniceine.

In 399 BC, the Athenian philosopher Socrates was sentenced to death and drank a preparation made with poison hemlock. The plant’s toxins disrupt nicotinic receptors at neuromuscular junctions, producing weakness and paralysis that can eventually stop the respiratory muscles. This makes the historical account more than a literary association: Conium maculatum is the plant traditionally identified with the execution.

Poison hemlock is a biennial herb native to Europe and North Africa but now naturalized in many regions, including North and South America and Australia. It can grow rapidly, reach about 8 feet, and often has hollow stems marked with dark reddish-purple blotches.

The word “hemlock” causes a major identification problem. Poison hemlock is an herbaceous member of the carrot family, unrelated to hemlock trees in the genus Tsuga. Water hemlock is also a different and highly toxic plant, belonging to the genus Cicuta.