Castor bean

Super Categories



Known Synonyms

Ricinus communis

Castor bean dust is one of the most potent occupational allergens, and one of the few that has sensitised more than 50% of an exposed workforce. It has also sensitised residents outside an animal feed mill from antigen in the air. There is some cross-reactivity of the antigens with those from green coffee beans. Contaminated sacking previously used for castor beans has caused sensitisation in carpet underfelt manufacturers, furniture upholsterers and green coffee processors.

Castor beans are the source of the poison ricin, which was used to assisinate Georgi Markov in 1978. He was a Bulgarian writer and dissident journalist who was living in London, and died after he was injected with ricin in the end of an umbrella while walking to work. The umbrella had been rigged to inject a poison ricin pellet under Markov’s skin.


In the 1940s the U.S. military experimented with using ricin as a possible warfare agent. In some reports ricin has possibly been used as a warfare agent in the 1980s in Iraq and more recently by terrorist organizations.

Agent Castor bean
Other Names
Ricinus communis
Sources of Exposure
Castor beans, castor oil and cake. Sacks previously containing castor beans
Jobs animal feed mill workers, dockers, seamen, laboratory workers.  Contaminated sacking used in underlay manufacturers and furniture makers and green coffee handlers
Epidemiological Studies

Ordman D , An outbreak of bronchial asthma in South Africa affecting more than 200 persons caused by castor bean dust from an oil-processing factory , Int Arch Allergy , 1955 ; 7 : 10-24

Romano C, Sulotto F, Piolatto G et al , Factors related to the development of sensitisation to green coffee and castor bean allergens among coffee workers , Clin Exp Allergy , 1995 ; 25 : 643-650

Air Measurements
Specific IgE/ Skin prick test

SPT and IgE often strongly positive. 3 major allergens have been identified

Thorpe SC, Kenemy DM, Panzani RC, McGurl B, Lord M , Allergy to castor bean 2. Identification of the major allergens in castor bean seeds , J Allergy Clin Immunol , 1988 ; 82 : 67-72

Panzani R, Johansson SGO , Results of skin test and RAST in allergy to a clinically potent allergen (castor bean) , Clin Allergy , 1986 ; 16 : 259-266

Biological Monitoring no data
Specific Challenge Davison AG, Britton MG, Forrester JA, Davies RJ, Hughes DTD , Asthma in merchant seamen and laboratory workers caused by allergy to castor beans: analysis of allergens , Clin Allergy , 1983 ; 13 : 553-561
Early References

Bernton HS , On occupational sensitisation to the castor bean , Am J Med Sci , 1923 ; 165 : 196-202

Figley KD, Elrod RM , Endemic asthma due to castor bean dust , JAMA , 1928 ; 90 : 79-82


An interesting paper shows that diffeerent species of castor bean have different allergenicity and using a less allergenic bean might be possible Fakhri ZI , Mean wheal diameter in skin tests for castor bean extracts in castor bean allergic workers of eastern Sudan. , J Soc Occup Med , 1989 ; 39 : 144-146

References for: Castor bean See published papers on "Castor bean" from this website.
Haz-Map information on: Castor bean See information on "Castor bean" from the HazMap (Information on Hazardous Chemicals and Occupational Diseases) website.

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