Common Name
Water Hemlock
Botanic Name
Cicuta douglasii, C. maculata- spotted water hemlock
Plant Family
Prefers wet marshy sites in meadows, along strems, irrigation ditches, often growing with its roots in water.
Animals Affected
Cattle, horses, sheep, humans
Toxic Principle
Cicutoxin, and cicutol, potent unsaturated alcohols, are found in all parts of the plant. The roots are highly poisonous at all times, and livestock consuming as little as 2 ounces of the root, will usually die. The toxin is rapidly absorbed from mucous membranes and the digestive tract. The toxin acts primarily on the brain affecting the inhibitory neurons causing violent convulsions and respiratory failure.
At least 4 major species of water hemlock occur in North America. They are stout, erect, hairless perennials growing to a height of 4-6 feet. Stems arise from a cluster of tuberous roots. The stems are hollow and compartmentalized, the partitions are compressed towards the root base. A yellow, turnip-smelling fluid oozes from the cut surface that contains the toxin. The leaves are alternate, 1-3 times pinnate with toothed edges, and leaf veins that run to the leaf notches. The flowers are showy, white loose umbels. The fruits are oval, flattened laterally with prominent ribs. All species of Cicuta should be considered highly toxic. Cicuta maculata is found predominantly in the eastern United States, while C. douglasii occurs more commonly in the western States. Cicuta maculata, also known as spotted water hemlock,poison parsnip,spotted cowbane,orspotted parsley has red stems.
Excessive salivation, vigorous chewing movements, and teeth grinding
Animals that experience severe convulsions from the water hemlock develop muscle degeneration.
Intravenous administration of sodium pentobarbital at the onset of seizures prevents lethal cardiac and skeletal muscle degeneration. Laxatives may be beneficial by helping to remove the plant from the digestive system. Vomiting should be induced in dogs and people suspected of eating water hemlock. Artificial respiration should be given where possible if respiratory failure occurs. The use of dilute acetic acid orally in cattle has been reported beneficial in neutralizing the toxin.
Cardiovascular system
Heart muscle degeneration develops in animals that experience convulsions. The more severe the convulsions the worse the heart degeneration, and the poorer the prognosis
Respiratory System
Death from respiratory paralysis.
Nervous System
Cicutoxin is a potent neurotoxin causing rapid onset of muscle tremors and violent convulsions. Death often occurs in a matter of 2-3 hours after the onset of clinical signs. Convulsive seizures and lateral recumbency precede death..
Ocular System
Dilated pupils
Sudden death, and finding of water hemlock parts in the rumen and stomach.
Special Notes
Fatalities have occurred in children who have sucked on the hollow stems of water hemlock. Fatalities occur when people mistakenly eat the tuberous roots of water hemlock for the edible root of common yampa (Perideridia gairdneri). The tuberous roots have also been mistaken for edible wild parsnip (Pastinaca sativa). The plant should be dug up and burned where possible. Spraying water hemlock with 2,4,-D herbicide will kill the plant, but it should be remembered that the herbicide may make the plant more palatable before it dies off.
Water hemlock stem sectioned to show
Water hemlock tuberous roots