Castor oil has been used for centuries as a laxative and all-purpose curative. Ironically, the same plant that makes possible this healthful oil also happens to be the world’s deadliest plant.
The Guinness Book of World Records bestowed this title upon the castor oil plant (Ricinus communis) because of its seeds. They contain the ultra-toxic chemical ricin. As few as 4-8 seeds is a lethal dose for an adult human. In purified form, a fatal dosage would be the size of a few grains of salt.
Photo credit: “Ricinus March 2010-1” by Alvesgaspar – Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons