The Most Poisonous Plant in the World

Castor oil seeds
Castor oil seeds-Ricinus communis

Title for the most poisonous plant in the world goes to the common Castor Plant. Yup, the same plant responsible for producing castor oil.

All parts of the plant are poisonous but it is the seeds containing ricin that have earned its number one position on the list of deadly plants.

A single seed can kill a human (though it usually requires more) but it isn’t a quick death. Abdominal pain, vomiting and bloody diarrhea can last from two to five days before a person finally succumbs to dehydration.

Animals fare slightly better than humans, only in that it takes more seeds to kill them. Body size doesn’t seem to be a factor. It requires four seeds to kill a rabbit, five to kill a sheep, six a horse, seven a pig and eleven for a cat. Ducks can consume a whopping eighty Castor seeds before things go seriously wrong.

Castor bean in garden

With large, showy, palm shaped leaves and thick stalks capable of growing 2-3 meters (6-9 feet) in a single season these tropical perennials, or cool weather annuals, are highly prized as decorative additions to public landscaping and private gardens, as well as a commercial source for medicinal castor oil.

To make the medicine children love to hate, the toxic protein ricin is removed from the seeds during the process of extracting the oil. Harvesting the plant can be risky with workers sometimes suffering permanent nerve damage.

Castor Oil is used medicinally as a laxative. Other uses of Castor Oil and its by products include soaps, perfume, polish, automotive fluids, paint, ink, plastic, wax.  It is also used as a food additive and preservative.

The name Castor Oil is thought to come from “castoreum” a perfume base originally sourced from the perineal glands of a beaver. Later castoreum was replaced by the oil derived from a castor bean, a change that the poor beavers no doubt applauded with much tail slapping.

A playful beaver

Castor Bean plant seeds are commonly sold on racks in department and nursery stores under various names and varieties. Look for Ricinus in the Latin name if there is any doubt. And of course, whatever you do, keep them away from children and animals.