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Conium maculatum

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Plant Profile

Flowering Months:
Apiaceae (Carrot)
Life Cycle:
Annual, Biennial or Perennial
Maximum Size:
3 metres tall
Ditches, fields, meadows, riverbanks, roadsides, wasteland, waterside, wetland.

White, 5 petals
White umbels to 6cm wide with small bracts underneath.
Dark browns small, smooth, ridged and flattened capsule. Each fruit contains two seeds. Up to 3mm in length.
Bipinnate, hairy, fern-like leaves. Triangular, up to 20 inches (50cm) long.
The whole plant smells foetid.
Other Names:
Beaver Poison, Beaver Poisoner, Break-your-mother's-heart, Bunk, Caise, California Fern, Carrot Fern, Common Hemlock, Conium, Deadly Hemlock, Deadly Hemlock, Devil's Bread, Devil's Flower, Devil's Porridge, Gypsy Flower, Herb Bennet, Hever, Kecksies, Kex, Lady's Lace, Musquash Root, Nebraska Fern, Poison Hemlock, Poison Parsley, Poison Stinkweed, Scabby Hands, Snake-weed, Spotted Corobane, Spotted Cowbane, Spotted Hemlock, Spotted Parsley, Winter Fern, Wode Whistle, Woomlick.
Frequency (UK):

Other Information


Conium maculatum, also known as poison hemlock, is a highly toxic perennial herb that is native to Europe and Asia. It can grow up to a height of 3 meters. The plant has a distinctive smell and is characterized by its large, finely divided leaves and clusters of small white flowers. The plant has a long history of use as a poison, and it was used to execute criminals in ancient Greece. All parts of the plant are toxic, but the highest concentration of the poison is found in the seeds and roots. Symptoms of poisoning include muscle weakness and paralysis, which can lead to respiratory failure and death. It is considered an invasive species in many parts of the world, particularly in North America.


Hemlock, also known as Conium maculatum, is a highly poisonous plant native to Europe and Asia. It has been used in traditional medicine for various purposes, including as a sedative, anesthetic, and painkiller. However, due to its toxic nature, hemlock can be lethal if ingested in large amounts.

Description of Hemlock

Hemlock is a biennial herb that can grow up to 2-3 meters tall. It has a smooth, hollow stem with purple spots and branches out into multiple umbels of small white flowers. The leaves are finely divided and feathery, and the plant has a distinct unpleasant odor.

Toxicity of Hemlock

Hemlock is a poisonous plant that contains several toxic alkaloids, including coniine, conhydrine, and gamma-coniceine. These alkaloids act as neuromuscular blockers, which means they disrupt the normal functioning of muscles and nerves.

Symptoms of Hemlock Poisoning

If hemlock is ingested, it can cause a range of symptoms, including nausea, vomiting, abdominal pain, diarrhea, confusion, tremors, seizures, respiratory failure, and ultimately, death. The symptoms can occur within 15-60 minutes of ingestion, and death can occur within 2-3 hours.

Uses of Hemlock

Despite its toxic nature, hemlock has been used in traditional medicine for various purposes. For example, in ancient Greece, hemlock was used as a sedative and painkiller. It was also used in Europe during the Middle Ages as an anesthetic for surgery. Today, homeopathic practitioners use hemlock to treat a range of conditions, including anxiety, depression, insomnia, and menstrual cramps.

Prevention of Hemlock Poisoning

The best way to prevent hemlock poisoning is to avoid handling or ingesting the plant. If you come into contact with hemlock, it is important to wash your hands thoroughly to prevent accidental ingestion. If you suspect that someone has ingested hemlock, seek medical attention immediately. There is no antidote for hemlock poisoning, and treatment consists of supportive care, such as respiratory support, IV fluids, and activated charcoal.

More Information

Hemlock is also known for its infamous role in history as the poison used to execute the Greek philosopher Socrates. According to the accounts of his trial and execution, Socrates was given a cup of hemlock tea to drink, which caused his death within a few hours.

Hemlock has also been used in literature and art. In William Shakespeare's play Hamlet, the character Claudius uses hemlock to poison Hamlet's father. In the painting "The Death of Socrates" by Jacques-Louis David, Socrates is depicted holding a cup of hemlock before his execution.

It's important to note that hemlock can easily be mistaken for other plants, such as wild carrot or wild parsley, which can also be poisonous. Therefore, it's important to be cautious when foraging for wild plants and to properly identify them before consumption.

In addition to its toxicity, hemlock has also been identified as an invasive species in some parts of North America. It can quickly spread and outcompete native plant species, causing ecological damage.

In addition to its traditional medicinal uses, hemlock has also been studied for its potential pharmacological properties. Research has shown that some of the compounds found in hemlock may have anti-inflammatory, analgesic, and antitumor effects. However, due to the toxicity of hemlock, any potential therapeutic use would need to be carefully evaluated and monitored.

Hemlock has also been used as a natural insecticide, as the alkaloids found in the plant can be toxic to insects. However, the use of hemlock as an insecticide is not recommended, as it can also harm beneficial insects and other wildlife.

Hemlock poisoning can occur in both humans and animals. Livestock such as cattle, sheep, and horses are particularly susceptible to hemlock poisoning, and it is important to monitor pastures and remove any hemlock plants. Pets such as dogs and cats can also be affected by hemlock poisoning, and it is important to keep an eye on them when outside and to contact a veterinarian if any symptoms of poisoning are observed.

Overall, while hemlock has a rich history and potential medicinal properties, it remains a highly toxic plant that should be avoided. Proper identification of plants and caution when foraging are important steps to prevent accidental ingestion. Additionally, efforts to control the spread of hemlock as an invasive species and prevent livestock and pet poisoning are necessary to protect both human and animal health.

Facts about Hemlock

  • Hemlock, also known as Conium maculatum, is a highly poisonous plant native to Europe and Asia.
  • The plant contains toxic alkaloids, which act as neuromuscular blockers and can cause symptoms such as nausea, vomiting, confusion, tremors, and respiratory failure if ingested.
  • Hemlock has a notable place in history and literature, including its use in the execution of the Greek philosopher Socrates and its depiction in William Shakespeare's play Hamlet.
  • Hemlock can be easily mistaken for other plants, such as wild carrot or wild parsley, which can also be poisonous.

Hemlock is a highly poisonous plant that should be avoided due to its toxic nature. While it has been used in traditional medicine and has a place in history and literature, hemlock remains a dangerous plant that can be lethal if ingested. It's important to properly identify plants before consuming them and to seek medical attention immediately if hemlock poisoning is suspected. Additionally, efforts to control the spread of hemlock as an invasive species and prevent livestock and pet poisoning are necessary to protect both human and animal health.


Hemlock filmed at Grantham Services Northbound, Lincolnshire on the 28th June 2022.


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Distribution Map

Reproduced by kind permission of the BSBI.

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