Hemlock
Coniine is a toxic alkaloid, found in plants like poison hemlock a hardy herbaceous flowering plant native to Europe and North Africa and capable of growing a a wide variety of environments. All parts of the plant are toxic, especially the seeds and roots.
It affects the central nervous system, with death caused by respiratory paralysis. Famously, Socrates was sentenced to death by drinking coniine prepared from hemlock.
Characters poisoned by coniine[]
- Five Little Pigs - Amyas Crale. The book also mentions Socrates.