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Identifying the Symptoms of Ricin Exposure

Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

Concern about the use of the toxin ricin as a terrorist weapon have surfaced following media reports of isolated findings and poisonings related to this substance. Ricin is a naturally occurring toxin that is found in castor beans. Ricin poisoning may occur from chewing and swallowing castor beans, and the toxic substance can also be obtained the waste material that remains after processing castor beans to produce castor oil.

Ricin can take many forms: It can be a powder, a mist, a pill or pellet, and can be dissolved in water and other liquids. This means that a person can contract ricin poisoning via inhalation or ingestion; the initial symptoms of ricin poisoning depend upon both the degree and route of exposure. Accidental exposure to ricin unrelated to the ingestion of castor beans would be extremely unlikely to occur.

If ricin is inhaled, symptoms typically begin within eight hours of exposure and include difficulty breathing, fever, cough, nausea, sweating, and a feeling of tightness in the chest. The skin may turn blue due to the decreased oxygenation of blood resulting from fluid buildup (edema) in the lungs. Low blood pressureand respiratory failure may ultimately occur.

Learn symptoms of ricin poisoning from ingestion »

What ricin is

• Ricin is a poison that can be made from the waste left over from processing castor beans.



• It can be in the form of a powder, a mist, or a pellet, or it can be dissolved in water or weak acid.



• It is a stable substance. For example, it is not affected much by extreme conditions such as very hot or very cold temperatures.

Where ricin is found and how it is used

• Castor beans are processed throughout the world to make castor oil. Ricin is part of the waste "mash" produced when castor oil is made.



• Ricin has some potential medical uses, such as bone marrow transplants and cancer treatment (to kill cancer cells).

How you could be exposed to ricin

• It would take a deliberate act to make ricin and use it to poison people. Accidental exposure to ricin is highly unlikely.



• People can breathe in ricin mist or powder and be poisoned.



• Ricin can also get into water or food and then be swallowed.



• Pellets of ricin, or ricin dissolved in a liquid, can be injected into people's bodies.



• Depending on the route of exposure (such as injection or inhalation), as little as 500 micrograms of ricin could be enough to kill an adult. A 500-microgram dose of ricin would be about the size of the head of a pin. A greater amount would likely be needed to kill people if the ricin were swallowed.



• In 1978, Georgi Markov, a Bulgarian writer and journalist who was living in London, died after he was attacked by a man with an umbrella. The umbrella had been rigged to inject a poison ricin pellet under Markov's skin.



• Some reports have indicated that ricin may have been used in the Iran-Iraq war during the 1980s and that quantities of ricin were found in Al Qaeda caves in Afghanistan.



• Ricin poisoning is not contagious. It cannot be spread from person to person through casual contact.