Most viewers probably weren't overly crushed after watching King Joffrey ingest poison on Game of Thrones this season. (Yeah, yeah, spoilers.) But a few chemists watched the Purple Wedding and wondered, "Wait, what kind of poison was that?"
The American Chemical Society did a little investigating and figured it out:
In the books, George R. R. Martin calls the poison that gets Joffrey "the strangler," a substance extracted from the leaves of a foreign tree by a "wash of lime." The poison acts by causing its victims' neck muscles to clench so tightly that they asphyxiate.
Are there any poisons like that in the real world? As chemist Raychelle Burks explains, there are certainly quite a few plants that produce toxic alkaloids — including belladonna (known as "night shade"), hemlock, or the strychnine tree.
The first two — belladonna and hemlock — don't quite fit the bill, as the alkaloids they produce actually work as muscle relaxants.
That leaves the alkaloid strychnine. It's a poison that does cause your muscles to clench within 10 to 20 minutes — starting with the face and neck. And death comes from asphyxiation. Perfect. Granted, there are a few pesky inconsistencies here: the alkaloid in question comes from the seeds of the strychnine tree, not the leaves. And you can't really extract the alkaloid with "lime," as Marin writes — although you could, Burks points out, use limestone as part of the extraction process. Limestone, lime... close enough!