Aconitine is a highly poisonous alkaloid derived from various aconite species. It is a neurotoxin that opens TTX-sensitive Na+ channels in the heart and other tissues, and is used for creating models of cardiac arrhythmia. Aconitine was previously used as an antipyretic.
The Merck Index gives LD50s for mice: 0.166 mg/kg (intravenously); 0.328 mg/kg intraperitoneally (injected into the body cavity); approx. 1 mg/kg orally (ingested). In rats, the oral LD50 is given as 5.97 mg/kg. Oral doses as low as 1.5 – 6 mg aconitine were reported to be lethal in humans.
It is quickly absorbed via mucous membranes, but also via skin. Respiratory paralysis, in very high doses also cardiac arrest, leads to death. A few minutes after ingestion paresthesia starts, which includes tingling in the oral region. This extends to the whole body, starting from the extremities. Anesthesia, sweating and cooling of the body, nausea and vomiting and other similar symptoms follow. Sometimes there is strong pain, accompanied by cramps, or diarrhea. There is no antidote, so only the symptoms can be treated.
Aconitine was probably made most famous by its use in Oscar Wilde's 1891 story Lord Arthur Savile's Crime.