Water Hemlock
What is water hemlock?
Key facts
Water hemlock is a highly poisonous wetland plant in the carrot family, known for its white umbrella-shaped flowers and toxic roots.
Context
Water hemlock is a poisonous plant in the carrot/parsley family, with the best-known North American species being common water hemlock (Cicuta maculata) [1]. It is a wetland plant with small white flowers in umbrella-shaped clusters, and its roots are especially toxic; ingestion of any part can be lethal [1]. The plant contains cicutoxin, which acts rapidly on the central nervous system [1]. It is described as the most toxic plant in North America [2]. Common water hemlock grows to about 2.5 metres (8 feet) tall [1].
Documented claims
- The roots are especially toxic; ingestion of any part can be lethal. [1]
- Water hemlock contains cicutoxin, which acts rapidly on the central nervous system. [1]
- It is described as the most toxic plant in North America. [2]
- Common water hemlock grows to about 2.5 metres (8 feet) tall. [1]
- The flowers are small and white and arranged in umbels. [2]
Questions and answers
Is water hemlock poisonous to touch?
The sources do not specify whether touching is harmful, but ingestion of any part is lethal [1].
Where does water hemlock grow in Canada?
The sources do not specify Canadian locations, but it grows in wet meadows, swamps, and shoreline thickets [4].
What is the mortality rate for water hemlock?
The sources do not provide a mortality rate, but ingestion can be lethal [1].
How many people died from hemlock?
The sources do not provide mortality statistics.
Sources
- Water Hemlock — fs.usda.gov (retrieved August 3, 2026)
- [PDF] water hemlock - Natural Resources Conservation Service — nrcs.usda.gov (retrieved August 3, 2026)
- Cicuta maculata - Plant Toolbox - NC State University — plants.ces.ncsu.edu (retrieved August 3, 2026)
- Water hemlock (Cicuta douglasii) - USDA ARS — ars.usda.gov (retrieved August 3, 2026)