[3] The leaves are alternate and compound pinnate; the secondary veins of the leaflets end at the bases instead of the tips of the teeth.

Water hemlock is most abundant in British Columbia,[6] and is indigenous to North America,[2] where it grows primarily from the base of the Rocky Mountains to the Pacific coast, stretching from Alaska all the way to California.

Early symptoms of cicutoxin poisoning include excessive salivation, frothing at the mouth, nervousness, and incoordination.

[2] Ingestion of green materials of western water hemlock in amounts equivalent to about 0.1% of a person's body weight can even lead to death.

[2] These characteristics, along with the fact that it grows in moist areas, make the plant very attractive, but deadly, to grazing animals.