Coniine is a toxic alkaloid primarily found in the plant poison hemlock (Conium maculatum). It is a colorless, oily liquid with a strong, unpleasant odor. Coniine affects the nervous system, leading to symptoms such as muscle paralysis and respiratory failure, which can be fatal if ingested in sufficient quantities. This compound was historically used in ancient Greece, notably associated with the execution of the philosopher Socrates. Today, coniine is studied for its effects on the body and its potential applications in pharmacology, although its toxicity limits its use in medicine.