Water Hemlock
If you know anything about water hemlock, then it’s likely that you’re familiar with the plant’s claim to fame: Socrates famously drank it to commit suicide.
According to the United States Department of Agriculture (USDA), this plant contains the toxin cicutoxin, which, when ingested, acts directly on the central nervous system.
In the most extreme cases, that could result in grand mal seizures and death.
