Euphorbia poisonii

Euphorbia poisonii is a highly toxic and succulent member of the large and varied Spurge genus of plants. It is native to northern Nigeria, where local farmers extract its latex for use as a pesticide, potent against any animal that enters the field. Its powerful and painful nature mandates fencing and clear marking of fields using the poison, but the produce is safe to eat as the toxin decomposes after a few days of exposure to air.

Toxic Activity
The active toxin Resiniferatoxin binds to pain receptors in the same way as capsaicin but much more powerfully. It stimulates the neurons to fire repeatedly until the neuron dies, causing searing pain and sending the victim into severe anaphylactic shock.

Due to its selective nature of binding and killing pain receptors while leaving other nerve cells intact, resiniferatoxin is currently being researched as a possible treatment for chronic pain.