Bottle of Strychnine Sulfate tablets in a brown glass bottle with cork top closure.

Strychnine is a highly toxic, colorless, crystalline alkaloid used today as a pesticide for rodents or birds. When inhaled, swallowed, or absorbed through the eyes or mouth, strychnine causes muscular convulsions and eventually death through asphyxia.

While it is no longer used medicinally, strychnine had been used in the late 19th century and early 20th century in small doses to strengthen muscle contractions, such as a heart and bowel stimulant, as an athletic performance-enhancing drug, and to treat paralyzed muscles.