Shusta, D - Castor bean

Ricinus communis L.

Daniel Shusta


Identification and Development


Ricinus comminus L. is classified as such:


Kingdom Plantae – Plants
Subkingdom Tracheobionta – Vascular plants
Superdivision Spermatophyta – Seed plants
Division Magnoliophyta – Flowering plants
Class Magnoliopsida – Dicotyledons
Subclass Rosidae
Order Euphorbiales
Family Euphorbiaceae – Spurge family
Genus Ricinus L. – ricinus
Species Ricinus communis L. – castorbean

Ricinus communis L. is the only species in its genus, though there are hundreds of natural varieties and many cultivars.



The leaves are large and palmate, having 5-11 lobes. The plant can grow 10 to 30 meters in the tropics, though when grown as a crop, the beans can be harvested when it is only 1.2 to 1.5 meters high (4 to 5 feet).


Though in the tropics, Ricinus communis L. grows as a perennial, in more temperate climates it typically behaves as an annual. It becomes reproductive in the first season (within six months), and can flower year round, barring frost. It produces fruit with soft spikes that will mature into seeds, the castor bean (which is not really a bean).




Ricinus communis L. has been a cultivated species for thousands of years, with indications that the ancient Egyptians used castor oil. It is now naturalized throughout the tropical habitats, and can grow in temperate climates as well. It grows wild in much of the United States, including Ohio, and particularly in the South. In some areas it is classified as invasive, especially in riparian areas and on disturbed land.



It was cultivated in the United States until the 1970s when concern over ricin and allergens caused it to fall out of favor. It is now cultivated chiefly in India and Brazil. However, with the rise of genetic engineering and biotechnology there is research into genetically removing ricin and the other allergens from the seed, renewing interest in growing Ricinus communis L. in the United States.




Ricinus communis is best known for its poison, ricin, which is one of the most deadly biological poisons known. That both Ricinus communis is easily found and ricin is extracted make ricin one of the more attracted bioterrorism substances. Ricin recently came on the world stage in 2003 and 2004, when letters containing ricin powder were received by the mail office for US Senator Bill Frist and for the White House.


Ricin poisoning can occur through ingestion, inhalation, and injection. The most common situation for ricin poisoning is consumption of the castor beans. The number of beans to cause poisoning and to cause death depend on variations in the bean and variations in the person, though around 8 beans are needed to cause death. Ricin poisoning has no cure and no treatment; the only thing that can be done is treatment of the symptoms.


Ricin works by entering a cell and inactivating ribosomes. Without ribosomes, protein production ceases, and cell death soon follows. This is a gross oversimplification, and for a more detailed description (but not overwhelmingly so) I would strongly recommend


Castor Oil


Castor oil is extracted from the seed of Ricinus communis. Despite that the seed has the highest concentration of ricin in the plant, castor oil is safe when used properly. Though it is a vegetable oil, it is not edible.


Historically, castor oil has been used for millennia as a purgative and laxative. It has had various other uses as folk medicine, though the discovery of ricin in the last century has discouraged that. During the 1920s, fascist mobs in Italy would pour castor oil down victim's throats as a torture of sorts. While it would normally just cause diarrhea, sometimes the oil was mixed with gasoline, which often caused death.


Currently, castor oil is used for a variety of industrial purposes, including cosmetics, hair products, soap, lubricants, greases, and embalming fluids. It is especially useful in countries with little to no access to petrochemicals.


Yes, I am a horrible, horrible person for not having this completed until now. Moving on.


Being of commercial use to humans, Ricinus communis L. has been intentionally spread to every continent for cultivation purposes. The primary producers of this crop are India, China, and Brazil, mostly because there are little to no regulations concerning occupational safety and the labor is cheap. The harvesters in these countries frequently suffer from health problems due to the ricin and allergens from the castor bean plant.


Ricinus is a nuisance for farmers growing livestock. Being unrecognizable to many of our domesticated animals, Ricinus is usually ignored. Occasionally, though, perhaps a castor bean falls into the feed or the animal is particularly hungry, an animal gets ricin poisoning, and sometimes it is fatal. Horses are especially vulnerable, requiring less ricin to be fatal than even humans. This is still uncommon, despite that neglected farmland is one of the more ideal growing habitats for Ricinus.


It now grows wild in much of the world, being found in many tropical and subtropical biomes and some temperate biomes. It is considered invasive in many parts of the world, frequently supplanting existing plants as one of the primary succession plants after a disturbance—for example its seeds are quick to germinate after a fire. Disturbance is often required, though, for Ricinus to establish itself; otherwise other grasses and plants will overcome it. Even after it has established itself, if there are no further disturbances it will be overcome. It is common to find Ricinus in a flood zone, in riparian areas, or along roadsides.


The castor bean plant is not frost hardy, limiting its range to the hotter biomes. It can grow in areas with as little as 2.0 dm (approximately 8 inches) of annual precipitation, but prefers wetter areas, with a mean (of 68 cases) of 12.7 dm (50 inches). It can withstand a pH of about 4.5 to 8.3—the mean was 6.5 (of 29 cases). All in all, in areas that do not freeze, there are not many habitats that cannot support Ricinus communis.


According to the previous criteria, Ricinus can be found in the following biomes: Tropical and Subtropical Moist Broadleaf Forests; Tropical and Subtropical Dry Broadleaf Forests; Tropical & Suptropical Coniferous Forests; Temperate Broadleaf & Mixed Forest; Temperate Coniferous Forests; Tropical & Subtropical Grasslands, Savannas, & Shrublands; Temperate Grasslands, Savannas, & Shrublands; Flooded Grasslands & Savannas; Mediterranean Forests, Woodlands & Scrub; Deserts & Xeric Shrublands; and Mangroves. It isn’t usually found in the entirety of these biomes, only the parts that don’t freeze and get enough water.


Frankly, as Ricinus’s habitat covers a solid quarter of the planet’s landmass, if not more, and primarily consists of recently disturbed areas in hot, wet climates, it’s in little danger as far as climate change or human intervention is concerned. While climate change will indeed put much of its sub-tropical locations into a drought that may starve it of water, there are going to be plenty of other locations in the tropical locations and near human habitation that will be wetter and hotter than ever. And if it ever even remotely becomes threatened, there would be a huge industrial and agricultural interest in preserving at least the domestic strands for cultivation. As long as it continues to be useful, and as long as we keep disturbing the landscape, Ricinus’s future is pretty well assured.

  • The PLANTS Database [Internet]. Baton Rouge(LA): USDA, NRCS; [cited 2008 Feb. 9]. Available from:
  • Duke J M. Ricinus communis L [Internet]. West Lafayette (IN): Purdue University; [cited 2008 Feb. 17]. Available from:
  • Ecology of Ricinus communis [Internet]. National Biological Information Infrastructure & IUCN/SSC Invasive Species Specialist Group; [cited 2008 Feb. 16]. Available from
  • Castor oil. In: Encyclopedia Britannica Online. [Internet]. Encyclopedia Britannica: [cited 2008 Feb. 14]. Availabe from:
  • Castor-oil plant. In: Encyclopedia Britannica Online. [Internet]. Encyclopedia Britannica: [cited 2008 Feb. 14]. Availabe from:
  • Audi J, Belson M, Patel M, Schier J, Osterloh J. 2005. Ricin poisoning - A comprehensive review. JAMA-J AM MED ASSOC 294(18):2342-2351.
  • Ogunniyi D. 2006. Castor oil: vital industrial raw material. BIORESOURCE TECHNOL 97(9):1086-1091.
  • Johnson W. 2007. Final report on the safety assessment of ricinus communis (castor) seed oil, hydrogenated castor oil, glyceryl ricinoleate, glyceryl ricinoleate SE, ricinoleic acid, potassium ricinoleate, sodium ricinoleate, zinc ricinoleate, cetyl ricinoleate, ethyl ricinoleate, glycol ricinoleate, isopropyl ricinoleate, methyl ricinoleate, and octyldodecyl ricinoleate. INT J TOXICOL 26:31-77.
  • Adams C. Did Mussolini use castor oil as an instrument of torture?. The Straight Dope [Internet]; [cited 2008 Feb. 18]. Available from:
  • Ricinus communis page. Missouri Plants [Internet]; [cited 2008 Feb. 19.] Available from:
  • High-Tech Castor Plants May pen Door to Domestic Production. USDA:Aricultural Research [Internet]; [cited 2008 Feb. 9]. Available from: