Aconitum, also known as monkshood, wolf's bane, Queen of all Poisons and several other names, is a genus of over 250 species of perennial flowering plants native to the mountains of the northern hemisphere. It is extremely poisonous. Several cultures use one or another of the species as arrow poisons, including the Minaro, Ainu, Chinese and Aleuts. Cleopatra used aconite to kill her brother Ptolemy XIV, so she could put her son on his throne. It has been used in multiple real and fictional murders. One of the most recognizable is Monk’s Hood by Ellis Peters (1980), which I have just been reading.  It also features prominently in wolfman and vampire stories.

Monks' Hood photo by Bernd Haynold

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Marked symptoms appear within one hour with ingestion of the poison. Death may occur instantaneously with large doses or within two to six hours in lower doses (20 to 40 mL of tincture may prove fatal) The initial signs are gastrointestinal including nausea, vomiting, and diarrhea, followed by a sensation of burning, tingling, and numbness in the mouth and face, and of burning in the abdomen.  In severe poisonings pronounced motor weakness occurs and cutaneous sensations of tingling and numbness spread to the limbs. Cardiovascular features include hypotension, bradycardia, and arrhythmia. Other features may include sweating, dizziness, difficulty breathing, headache, and confusion. The main causes of death are ventricular arrhythmias and asystole, paralysis of the heart or of the respiratory center. The only post-mortem signs are those of asphyxia.

Poisoning may also occur by picking the leaves without wearing gloves, as the toxin is absorbed easily through the skin. In this event, there will be no gastrointestinal effects. Tingling will start at the point of absorption and extend up the arm to the shoulder, after which the heart will start to be affected.