Water Hemlock (Cowbane) Roots of the Water Hemlock
Springtime brings warm weather and many enjoy the great outdoors. Hikers and outdoor enthusiasts often go into the woods with minimal supplies. Some have knowledge of edible plants. Queen Anne ’s Lace is a plant where the root can be eaten but it can be confused with Water Hemlock which is one of the most toxic plants in North America. Let’s delve a little deeper.
Water Hemlock is of the Cicuta species. It is found along streams and in wet, swampy areas. The roots might be mistaken for carrots or parsnips.
Mechanism of toxicity: The principal toxin, cicutoxin “belongs to a group of C 17 conjugated polyacetylenes. They act as (noncompetitive) gamma-aminobutyric acid antagonists in the Central Nervous System, resulting in unabated neuronal depolarization that can lead to seizures.” (PubMed)
Because Water Hemlock grows in a moist environment it is easy to dig up the roots which are often mistaken for carrots or parsnips and when consumed this plant can cause significant, severe and potentially life threatening effects. The largest concentration of toxin is in the roots. Nausea and vomiting comes a short time after ingestion, usually within the hour. Symptoms can intensify to agitation, mydriasis, delirium, tachycardia, excessive salivation, respiratory distress and most severe seizures which can be refractory status epilepticus leading to death. The onset of seizure activity can occur from 5 minutes to 2 hours.
Treatment is symptomatic and supportive. If seizures occur use benzodiazepines and phenobarbital as a second line of defense.
http://emedicine.medscape.com/article/821362. MedScape. Hemlock Poisoning
http://www.ncbi.nlm.nih.gov/pubmed/19514873. PubMed PMID: 19514873 [PubMed – indexed for Medline] Poisoning due to water hemlock. Clin Toxicol (Phila.), 2009 Apr, 47 (4): 270 -8.
Micromedex ® Healthcare Series. (Volume 168). Truven Health Analytics.
This Question prepared by: Denese Britt, BSN, MS, CSPI
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Donna Seger, MD
Tennessee Poison Center
Poison Help Hotline: 1-800-222-1222