The Toxicity of Castor Beans


The castor bean plant (Ricinus communis) grows to a height of 15 feet in tropical and sub-tropical areas. The leaves of the plant attain a width of up to 20 inches. The plant sports both male and female red flowers. Following flowering, the plant produces spiny seed pods. Often grown as an ornamental, it poses a serious danger to children and animals who may inadvertently consume the highly toxic mottled seeds.

Castor Beans

Castor beans mature within a spiny pod. Upon maturity, the pod explodes and forces the seed out to fly through the air. Each seed sports its own distinct mottled pattern, in brown, tan and white.


Within each castor bean is a toxic substance known as ricin. Ricin is considered to be a cytotoxin. Castor beans hold the distinction of being one of the most poisonous natural substances in the world. Ricin is considered 6,000 times more toxic than cyanide, according to Wayne's World at Palomar College.

Consumption Results

A castor bean can safely pass through the intestinal tract of a mammal without causing poisoning if the hard outer shell is not broken. Once the shell is broken, the ricin can leak out and be absorbed by the intestinal tract. If a small child consumes only one castor bean, the result is often death. An adult can die after consuming only four castor beans.


Symptoms manifest within hours of ingestion. The victim will suffer vomiting, diarrhea and severe abdominal pain. As the days pass, the victim suffers dehydration and low blood pressure. Death usually results within three to five days, according to Cornell University.

Insects, Birds and Animal Toxcity

Insects are not immune to the effects of ricin poisoning from the castor bean plant. Aphids who decide to dine on the plant's sap die within 24 hours. Horses, cattle, sheep, ducks, geese and pigs are often poisoned by consuming not only the beans of the plant but also the foliage and stalks. Unfortunately, entire flocks of a 1,000 ducks and geese are often poisoned by accidentally feeding on castor bean plants, according to the University of Illinois.


Murders utilizing the ricin acquired from the castor bean have been committed in history. The journalist, Georgi Markov, was stabbed in London using the tip of an umbrella that contained ricin. He later died from the poison.

Keywords: castor bean toxicity, ricin poison, castor bean poisoning

About this Author

Kimberly Sharpe is a freelance writer with a diverse background. She has worked as a Web writer for the past four years. She writes extensively for Associated Content where she is both a featured home improvement contributor (with special emphasis on gardening) and a parenting contributor. She also writes for Helium. She has worked professionally in the animal care and gardening fields.