Strychnine

Strychnine (, STRIK-neen, -⁠nin, US chiefly -⁠nyne) is a highly toxic, colorless, bitter, crystalline alkaloid used as a pesticide, particularly for killing small vertebrates such as birds and rodents. Strychnine, when inhaled, swallowed, or absorbed through the eyes or mouth, causes poisoning which results in muscular convulsions and eventually death through asphyxia. While it is no longer used medicinally, it was used historically in small doses to strengthen muscle contractions, such as a heart and bowel stimulant and performance-enhancing drug. The most common source is from the seeds of the Strychnos nux-vomica tree.