Practical ecological knowledge for the temperate reader.

Douglas' water-hemlock - Cicuta douglasii

Family: APIACEAE - Carrot Family [E-flora]
Other Names: western water hemlock.[E-flora]


General: Stout perennial herb from a taproot or cluster of tuberous roots; stems solitary or few together from a tuberous-thickened and chambered base, leafy, glabrous, 0.5-2 m tall.[IFBC-E-flora]
Leaves: Basal and stem leaves divided 1-3 times, leaflets 3-4 times as long as broad, lanceolate to narrowly oblong or elliptic, these sharply pointed and toothed, 4-7 mm long; lateral veins ending at base of the teeth.[IFBC-E-flora]
Flowers: Inflorescence of several to many small, compact clusters forming several compound umbels; flowers white to greenish; involucral bracts mostly lacking.[IFBC-E-flora]
Fruits: Egg-shaped to orbicular, 2-4 mm long, glabrous, corky-thickened; ribs unequal, with a narrow raised border on edge of dark intervals.[IFBC-E-flora]

Plant 15–30 dm. Leaf: 1.5–4.5 dm, narrowly ovate to triangular-ovate, 1–2(3)-pinnate; leaflets 1–10(15) cm, linear to widely lanceolate, acute or acuminate, ± entire to coarsely serrate, areas surrounded by veins on abaxial surface rough-textured, generally some elongate. Inflorescence: umbels compound, terminal and lateral; peduncles 2–18 cm; rays 15–30(35), 2–8 cm; pedicels 20–30, 2–10 mm. Fruit: 2–4 mm, generally round; rib width >> intervals between.
2n=44. Wet places, generally aquatic; < 2800 m. North Coast, High North Coast Ranges, Inner North Coast Ranges, High Cascade Range, s Sierra Nevada Foothills, High Sierra Nevada, Central Coast, South Coast, Great Basin Floristic Province; to British Columbia, Montana. Jun–Sep [Online Interchange][Jepson2012]

Habitat / Range
Wet stream edges, ditches and marshes in the lowland, steppe and montane zones; common throughout BC except the Queen Charlotte Islands; N to AK and S to ID, NV and CA. [IFBC-E-flora]
Origin Status: Native [E-flora]

Distribution & Habitat
Cicuta spp. are found growing across North America and Europe. Typically, they grow in wet habitats usually alongside ponds and streams, in marshes or swamps, or areas that are swampy at least part of the year. Plants can also be found growing in water.[2][3] Of the four species, Cicuta maculata has the most widespread distribution occurring across the majority of North America. Cicuta bulbifera also has a relatively large distribution, found throughout Northern North America. Cicuta douglasii is found in the northwest corner of North America, while Cicuta virosa is only found in central Europe and in the far north of North America.[1][3] [Wiki]


This plant (with its eastern relative) has gained the reputation of being the most poisonous plant in the North Temperate Zone. The poison is concentrated mostly in the lower part of the stems or roots. It often causes death to livestock, and it is sometimes stated that a piece the size of a walnut will cause the death of a cow. Human beings have sometimes been poisoned by water hemlock, eating the underground parts, having mistaken them for various edible roots like parsnips. Children will sometimes do this, often with fatal results. It is said that a piece the size of a marble can cause death to a man. The poison is very virulent and causes violent convulsions. Vomiting should be induced at once and a strong cathartic administered. [Harrington]
Identification: Though poison and water hemlock usually have roots with chambers, Daisy Lee Bitter of Homer, Alaska, has found young roots of C. mackenzieana (virosa) that lack pronounced separations in the roots. She comments that the pungent odor of the roots is the most diagnostic characteristic in recognizing Cicuta.[Schofield]


Cicuta's toxic properties are attributed to cicutoxin, a resinlike substance found in all parts of the plants, but most concentrated in the root. [Schofield]
Properties: Poisonous Plants of the United States describes cicutoxin as ". . . a clear, brown, sticky substance with an acid reaction, which is soluble in alcohol, chloroform, ether and dilute alkalis." [Schofield]
The LD50 in mice administered cicutoxin by intraperitoneal injection is 48.3 mg per kg body weight (mg/kg); this compares with 5.9 mg/kg for mice given potassium cyanide by intraperitoneal injection, while the LD50 for arsenic via intraperitoneal injection in mice is 46.2 mg/kg.[22] The exact toxic dose of plant material in humans is unknown; it is thought ingestion of water hemlock in any quantity can result in poisoning and very small amounts may lead to death.[1]
Pharmacology: Cicutoxin depresses the respiratory system. Typical symptoms, which appear fifteen minutes to one hour after ingestion, include salivation, followed by diarrhea, tremors, severe stomach distress, and violent convulsions. Without treatment, one generally dies within eight hours of ingestion. [Schofield]
Upon consumption, both in humans and other species, the symptoms of poisoning are mainly characterized by generalized seizures.[1] The onset of symptoms following ingestion may be as soon as 15 minutes post ingestion. Initial symptoms reported may include nausea, vomiting, abdominal pain, tremors, confusion, weakness, dizziness, and drowsiness;[16][28] Symptoms of excess salivation, wheezing, respiratory distress, and absence of breathing have also been reported.[1][28][Wiki]
Treatment: Although vomiting should usually not be induced when convulsions are likely to occur (due to chance of aspiration into the lungs), inducing vomiting may be the only chance of survival. Marsh, et aI., in a United States Department of Agriculture bulletin, state that "if free vomiting is promptly induced, the patient is likely to recover." [Schofield]
Initial treatment of poisoning may include gastrointestinal decontamination with activated charcoal.[37] Decontamination is typically only performed if a potentially toxic amount of plant matter has been ingested up to one hour previously and the patient has a normal intact airway or has been intubated.[1] There is no specific antidote for water hemlock poisoning and treatment mainly consists of supportive care. Treatment may include control of seizures with the administration of a benzodiazepines such as lorazepam or diazepam, or if seizures are refractory to this treatment, a barbiturate such as phenobarbital is administered.[1] [Wiki]
Animals poisoned by Cicuta are given injections of anticonvulsant drugs to control convulsions and a purgative agent to remove toxins. Marsh et al. warn that "ordinarily the convulsions are so violent that nothing can be done for the animal” [Schofield]
Prognosis: Deaths usually occur from respiratory failure or ventricular fibrillation secondary to ongoing seizure activity;[1] fatalities have occurred within a few hours of ingestion.[3] Poisoned people who recover usually regain consciousness and seizures cease within 24 to 48 hours of poisoning, although seizures may persist for up to 96 hours.[1] There are occasional long-term effects such as retrograde amnesia of the events leading to intoxication and the intoxication itself.[8][28][32][34] Other ongoing mild effects may include restlessness, muscle weakness, twitching, and anxiety.[1][35] Complete resolution of symptoms may take a number of days or, in some cases, these ongoing symptoms may persist for months after poisoning.[1] [Wiki]

Edible Uses

Oswalt (1957) reports that the green leaves of one species of water-hemlock (C. mackenzieana) were cooked in water with fresh fish by Western Eskimo of Alaska, but the plant was otherwise not used. The roots were never eaten, and were considered poisonous to people, although small rodents are said to eat them. Considering the known toxicity of this plant, its use as food is not recommended under any circumstances. [Turner&Kuhnlein]

Medicinal Uses


Bella Coola: Roots used as a purgative. [Smith(1927)]
This is one of the most poisonous plants known to man. It contains cicutoxin, a violent convulsant acting directly on the central nervous system (Claus and Tyler, 1967). The Kwakiutl used it with caution as a purgative and to induce vomiting (Boas, 1966). The Salish may also have had such medicinal uses for it.[Turner&Bell1]


Young fir bark, burned, pulverized, and mixed with water in which waxwaxuli (Cicuta douglasii) had been rubbed, was taken for diarrhoea (Boas, 1966). [Turner&Bell2]]

Historical Usage

To induce permanent sterility, writes Weiner in Earth Medicine, Earth Foods, Cherokees chewed hemlock root for four consecutive days. Rafinesque, a botanist of the 1700s, said that a similar remedy was taken by Indians ". . . tired of life and desiring a speedy demise." Historians generally believe Socrates was killed by a different but equally deadly hemlock, C. maculatum. Conium was also used by medieval herbalists "to keep maiden's teats small," and to destroy lust. As an external application, it was once used for rheumatic pain.[Schofield]
Throughout the ages, hemlocks of various species have been used to execute both criminals and kings. Oregon Indians soaked arrows in Cicuta juice, rattlesnake venom, and decayed deer liver to poison tips for hunting. [Schofield]


Cicuta douglasii (DC.) Coult.+Rose
Family: Apiaceae
Seed and Pericarp
Mass of 1,000, g: 3.9
Oil, % dry wt: 16.9
Composition (GLC, Ag+ TLC), %: 16:0 – 4.6; 18:0 – 1.1; 18:1(6) – 39.3; 18:1(9) – 14.8; 18:2 – 39.5; 18:3 – 0.7 [LEO,2012]

Cicuta Sp.

"Habit: Perennial herb, glabrous; rhizome internally chambered, sap becoming +- red-brown in air, fibrous- or tuberous-rooted. Stem: erect, hollow. Leaf: blade oblong to triangular-ovate, 1--3-pinnate or ternate-pinnate, leaflets linear to lance-ovate, serrate or irregularly cut. Inflorescence: umbels compound; bracts generally 0; bractlets generally inconspicuous; rays, pedicels many, spreading. Flower: calyx lobes minute; petals wide, white, tips narrowed. Fruit: ovoid to spheric, +- compressed side-to-side; ribs low, corky, occasionally unequally spaced; oil tube 1 per rib-interval; fruit axis divided to base. Seed: face flat or concave.
Species In Genus: +- 4 species: Eurasia, North America. Etymology: (Ancient Latin name) Toxicity: TOXIC: the most lethally toxic native plant species." [Jepson]

Local Species;

Other, Non-local, B.C. Species


  1. [Duke]Duke Phytochemical Database, James A. Duke, Accessed Feb , 2014,
  2. [E-flora]
  3. [Jepson2012] Lincoln Constance & Margriet Wetherwax 2012, Cicuta, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on March 27, 2022.
  4. [LEO,2012]A.I. Glushenkova (ed.), Lipids, Lipophilic Components and Essential Oils from Plant Sources
  5. [Wiki] Cicuta - Accessed on Feb 9, 2014

Page last modified on Sunday, March 27, 2022 1:08 PM