Aconite (Aconitum napellus) is commonly referred to as monkshood because the top of the flower resembles the monastic head covering. But there's nothing holy about this plant. A perennial, it stands 2 to 6 feet (0.6 to 1.8 meters) tall and produces blue, white or flesh-colored bunches of flowers at the tops of its stalks. Every part of the aconite plant is laced with the toxin aconitine, making it dangerous to consume or even touch.
Poisonings from aconite are rare but typically occur when gardeners or backpackers mistake its white carrot-like root for horseradish or some other edible herb. Consuming the plant causes burning in the mouth followed by increased salivation, vomiting, diarrhea, a tingling sensation in the skin, blood pressure and heart irregularities, coma and sometimes death. Just touching aconite can cause tingling, numbness, and in severe cases, heart problems.
People have used aconite in the past to intentionally harm people or animals. Nazi scientists used the plant's toxin to poison bullets, while shepherds in ancient Greece laced bait and arrows with aconite to kill wolves that preyed on their stock. From this latter use came another common name, "wolfsbane." Fans of the Harry Potter series will recognize this as the plant Professor Snape brews to help Remus Lupin turn into a werewolf.