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Poison hemlock

Conium maculatum

Also calledHemlock

One of the most poisonous higher plants, famous as the poison that killed Socrates in 399 BC. Its alkaloid coniine paralyses the nerve-muscle junction and kills by respiratory failure. It has no safe medicinal use and is not for home use in any form.

Full natural-history sheet →

What it is used for

  • Pain (general)
    Traditional

    A 2017 review notes renewed research interest in coniine as a pain reliever without addictive effects; this is laboratory work only, with no human treatment. The plant itself is lethal and must not be used.2

Safety

Pregnancy
Contraindicated
Breastfeeding
Contraindicated
Children
Never; all parts are poisonous.

Do not use if

  • Any internal or external use

Side effects

  • Vomiting, salivation, trembling, convulsions, ascending paralysis, coma and death

Dangerous lookalikes

A common weed of the carrot family; accidental human poisonings are recorded, and the alkaloids have a characteristic mousy smell.

In the healing traditions

  • Ancient Athens

    Poison hemlock

    The poison chalice given to Socrates in 399 BC contained poison hemlock.

Active compounds

coniine
piperidine alkaloid; nicotinic acetylcholine receptor antagonist; the first alkaloid whose structure was established (1881) and the first synthesised (1886)
γ-coniceine
biosynthetic precursor of the other hemlock alkaloids
N-methylconiine, conhydrine, pseudoconhydrine
related piperidine alkaloids

History

Coniine's most famous victim was Socrates, sentenced to death by a chalice of poison hemlock in 399 BC. In chemistry coniine holds two records: the first alkaloid to have its structure established (1881) and the first to be synthesised (1886).

Sources

  1. 1.Vetter J. Poison hemlock (Conium maculatum L.). Food Chem Toxicol 2004
  2. 2.Hotti H et al. The killer of Socrates: Coniine and Related Alkaloids in the Plant Kingdom. Molecules 2017
  3. 3.Reynolds T. Hemlock alkaloids from Socrates to poison aloes. Phytochemistry 2005
  4. 4.Rizzi D et al. Clinical spectrum of accidental hemlock poisoning: neurotoxic manifestations, rhabdomyolysis and acute tubular necrosis. Nephrol Dial Transplant 1991
  5. 5.López TA et al. Biochemistry of hemlock (Conium maculatum L.) alkaloids and their acute and chronic toxicity in livestock. A review. Toxicon 1999
  6. 6.Green BT et al. Piperidine alkaloids: human and food animal teratogens. Food Chem Toxicol 2012

Reference, not prescription. Nothing here is medical advice. Herbs can interact with medicines and be dangerous in pregnancy; tell your doctor or pharmacist about anything you take.