Monkshood: A purple poison
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The bottom line
Monkshood flowers look beautiful. Swallowing any part of the plant or herbal products made from it could be deadly.
Prevention tips
Let your healthcare provider know about all medications you are taking, including herbal products.
If you are interested in foraging wild plants, join an organization with experienced members.
Never eat an unknown plant or berry without verification from a clear field guide or someone with experience.
Monskhood is dangerous and can be deadly. Do not manage symptoms at home if they occur.
Keep all plants out of the sight and reach of children.
Talk with your healthcare provider before using any herbal product.
Consult our plant guide for more tips.
This really happened
Case 1. An 81-year-old couple was brought to an emergency department. They had both eaten a salad containing what they thought was ground elder from their private garden. The plant was later identified as monkshood. When the man arrived, his heart and breathing had stopped. He was resuscitated. The woman was conscious and told the staff what they had recently eaten. After eating the salad, they both had tingling and burning of their fingers and toes, then nausea, abdominal pain, dry mouth, hoarseness, and general numbness. About 30 minutes after eating the salad, the husband collapsed and the woman had severe vomiting, so she called 911. Her blood pressure was low, and her heart was beating very fast. She received medicines for her heart rhythm and recovered (from Munnecom et al., 2011).
Case 2. A man in his 50s was found dead behind the steering wheel of his car, which was in a ditch 60 miles from his home. The autopsy found trauma to several parts of his body, but it did not appear that he had died due to a car crash. He had an elevated blood alcohol concentration, but no other drugs or toxins were initially found.
Five years later, his wife confessed to killing him. She had boiled monkshood leaves and stalks. She mixed this with a few tablets of triazolam (used for insomnia) in a bottle of wine. Her husband drank the wine at dinner. She found her husband lifeless 3–4 hours later. She put his body into the driver’s seat of their car. Sitting on the lap of the body, she drove the 60 miles, pushed the car into the ditch, and attempted to burn it before taking a taxi home. Toxicological testing of saved samples 5 years after the death found aconitine in the man’s urine, liver, and kidneys (from Van Landeghem et al., 2007).
Case 3. A 25-year-old man in good health took an afternoon walk with friends on an uninhabited island off the coast of Newfoundland, Canada. He ate some wildflowers with purple and pink petals along with some blackberries at 2:30 PM. The flowers were later identified as monkshood. At 5:00 PM he had nausea and abdominal pain and then vomited. He collapsed at 6:15 PM and could not be revived. Blood tests confirmed aconitine poisoning (from Pullela et al., 2008).
What is monkshood?
Monkshood (Aconitum napellus), also known as wolfsbane or aconite, is a perennial herb native to western and central Europe. It is often grown as an ornamental plant for its blue to dark purple flowers. All parts of the plant, especially the roots, contain toxins. Aconitine is the most dangerous of these toxins. Raw aconite plants are very poisonous. They are used in herbal medicine only after they are boiled or steamed to reduce their toxicity.
Aconitine poisoning is most common in Asia because of the widespread use of herbal medications. In Hong Kong, aconitine is responsible for the majority of serious poisonings from Chinese herbal preparations. Aconitine poisoning is rare in North America. When it does occur, it is usually because someone mistook the plant for an edible one or a child swallowed it.
What to do if someone has swallowed monkshood
If someone swallows monkshood or an herbal product made from it, use the webPOISONCONTROL® online tool to get help, or call your poison center at 1-800-222-1222. Whether online or by phone, expert guidance is always free, confidential, and available 24 hours a day. Do not make the person vomit.
Does monkshood have therapeutic benefits?
Alleged therapeutic uses of monkshood include treatment of joint and muscle pain. As a tincture applied to the skin, it is claimed to slow the heart rate in cardiac patients. Other claimed uses include reduction of fevers and cold symptoms. As wolfsbane, it was believed to repel werewolves (and real wolves).
What are the symptoms of monkshood poisoning?
Symptoms start within minutes to a few hours after swallowing. The biggest danger is that aconitine can quickly cause life-threatening changes in heart rhythm. Other symptoms can include numbness and tingling, slow or fast heart rate, and stomach symptoms such as nausea, vomiting, abdominal pain, and diarrhea. Abnormal heart rhythms and paralysis of the muscles used for breathing can lead to death. There is no specific antidote. Treatment focuses on managing symptoms and supporting the heart and breathing.
Does monkshood have therapeutic benefits?
The difference between a claimed therapeutic dose of aconitine and a toxic dose is very small. For example, a 66-year-old woman with no known heart disease obtained aconitine from an herbalist. She was instructed to make a tea with it to treat her osteoarthritis. About 90 minutes after drinking the tea, she developed numbness of her face, arms, and legs. This was rapidly followed by nausea, weakness, and chest pressure. In the emergency department, she had an abnormal heart rhythm. After 4 hours of treatment with medicines and electrical shocks to her heart, her heart rhythm returned to normal (from Lowe et al., 2005).
Some people have been poisoned after growing monkshood and taking it for its claimed health benefits. A 21-year-old man acquired monkshood plants after reading a book on herbal medicine. He ground up the roots of the plants and filled capsules with the dried material. He then took 1 capsule daily for several months to treat his anxiety. To increase the effects one evening, he swallowed 3 capsules and went to sleep. He awoke 5 hours later with generalized numbness, nausea, diarrhea, dizziness, chest pain, shortness of breath, and changes in color vision (he was seeing purple). His early symptoms likely went unnoticed because he was asleep. In the emergency department, his heart rate was very slow, and he had an abnormal heart rhythm. Blood tests confirmed aconitine poisoning. He spent 48 days in the hospital (from Moritz et al., 2005).
Is monkshood deadly?
The medical literature documents at least 42 deaths from exposure to Aconitum, including at least 3 cases in which death was caused by application of Aconitum onto broken skin. In most cases, the exposure was to herbal medicine preparations containing Aconitum. Death occurred within 2–7 hours of exposure.
Monkshood has been used since ancient times as a poison on spears and arrows for hunting and battle. Ancient Romans used it as a method of execution.