Water hemlock

Related Terms

Apiaceae (family), bulblet-bearing water hemlock, Cicuta, Cicuta bulbifera, Cicuta douglasii, Cicuta maculata, Cicuta virosa, cicutoxin, cowbane, fool's parsley, northern water hemlock, spotted water hemlock, water hemlock, western water hemlock.
Note: Several accidental poisonings have been reported due to confusion of water hemlock roots with turnip, parsnip, or wild carrot. Water hemlock (Cicuta spp.) should not be confused with poison hemlock (Conium spp.), although the species have similar common names and similar general appearance.

Background

Water hemlock grows in temperate wet, marshy areas in mainly North America. According to the U. S. Department of Agriculture (USDA), "water hemlock is the most violently toxic plant that grows in North America."
Water hemlock is sometimes mistaken for parsnips, due to the similar appearance of their white tuberous roots.
Although water hemlock was rarely used for headache according to traditional use, there is insufficient available evidence in humans or animals to support the use of water hemlock for any indication.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Dosing

Adults (18 years and older):
Avoid in all patients as water hemlock is highly toxic and may lead to death.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Interactions

Interactions with Drugs
Taking water hemlock by mouth may cause an explosive illness with seizures and convulsions that may lead to death. Caution is advised when combining water hemlock with anticonvulsive agents, or agents that may lower seizure threshold.
Taking water hemlock by mouth may cause orthostatic hypotension (decreased blood pressure upon standing) or tachycardia (increased heartbeat). In theory, water hemlock may interact with other cardiac (heart) agents.
Water hemlock may also cause rhabdomyolysis (breakdown of skeletal muscle due to injury), marked metabolic acidosis (acidic blood), or acute renal (kidney) failure. Based on these effects, caution is advised when taking water hemlock with agents that are excreted through the kidneys.
Water hemlock may also interact with sedatives, as neurologic lethargy (drowsiness), or unconsciousness that may lead to death has been reported.

Attribution

This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

Applefeld JJ, Caplan ES. A case of water hemlock poisoning. JACEP. 1979;8(10):401-403.
Carlton BE, Tufts E, Girard DE. Water hemlock poisoning complicated by rhabdomyolysis and renal failure. Clin.Toxicol. 1979;14(1):87-92.
From the Centers for Disease Control and Prevention. Water hemlock poisoning--Maine, 1992. JAMA 5-18-1994;271(19):1475.
Haupt H. [Poisonous and less poisonous plants. Conium maculatum and Cicuta virosa]. Kinderkrankenschwester. 2003;22(11):495-496.
Heath KB. A fatal case of apparent water hemlock poisoning. Vet.Hum.Toxicol. 2001;43(1):35-36.
Knutsen OH. Paszkowski P. New aspects in the treatment of water hemlock poisoning. J.Toxicol.Clin.Toxicol. 1984;22(2):157-166.
Koloshtivina OV. [Poisonings of children by water hemlock]. Med.Sestra. 1980;39(10):37-38.
Landers D, Seppi K, Blauer W. Seizures and death on a white river float trip. Report of water hemlock poisoning. West J.Med. 1985;142(5):637-640.
Lkhagvazhav Kh, Biambasuren Ch, Maslov AV. [Group poisoning by water hemlock]. Sud.Med.Ekspert. 1980;23(3):51-52.
Mack RB. Keats, Socrates and fool's parsley--water hemlock poisoning. N.C.Med.J. 1985;46(3):163-164.
Muratova LM. [Providing aid before the hospital stage to children with water hemlock poisoning]. Feldsher.Akush. 1981;46(5):38-40.
Rizzi D, Basile C, Di Maggio A, et al. Clinical spectrum of accidental hemlock poisoning: neurotoxic manifestations, rhabdomyolysis and acute tubular necrosis. Nephrol.Dial.Transplant. 1991;6(12):939-943.
Short J. Water hemlock poisoning. Emerg.Nurse 2006;14(7):18-19.
van Heijst AN, Pikaar SA, van Kesteren RG, et al. [Poisoning due to water hemlock (Cicuta virosa)]. Ned.Tijdschr.Geneeskd. 12-31-1983;127(53):2411-2413.
Water hemlock poisoning--Maine, 1992. MMWR Morb.Mortal.Wkly.Rep. 4-8-1994;43(13):229-231.