What Is Strychnine?

The CDC says strychnine is a strong poison, that only a small amount is needed to cause serious effects in people, and that strychnine poisoning can cause extremely serious health effects, including death. It says the main natural source of strychnine is the plant Strychnos nux-vomica, found in southern Asia and Australia, that it was once available in pill form to treat many illnesses, and that today it is used mainly as a pesticide.

The CDC says strychnine poisoning causes severe, painful spasms of muscles throughout the body, that the person is at first very excitable and in pain, and that eventually the muscles tire and the person cannot breathe. It says anyone who thinks they swallowed strychnine should not swallow more and should call 911 immediately, and should not force themselves to vomit or drink fluids. It says treatment involves decontamination and supportive medical care in a hospital, including intravenous fluids, medications for convulsions and spasms, and cooling measures for high temperature.

In the United States its registered use is narrow. The EPA said in a November 2022 proposed interim decision that strychnine is registered as a rodenticide for underground use to control pocket gophers, plus some other rodents under a special local need registration in Nevada, and that it does not have any aboveground uses. As of August 2026, the EPA lists strychnine registration review decisions as upcoming.