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Ricin Poisoning

Facts and Definition of Ricin

Patient Comments
  • Ricin is a potent toxin that has gained attention in recent years because it could be used as an agent of biological warfare or as a weapon of mass destruction (WMD).
  • Ricin is derived from the beans of the castor plant (Ricinus communis), and is part of the waste material called "white mash" that is left over from processing castor beans into castor oil.
  • Only a small amount of this poison can be lethal. Exposure arises when it is inhaled, ingested, or injected.
  • This type of poisoning is not an infectious disease, and it's not contagious (spread from person to person).
  • Symptoms of ricin poisoning depend upon the amount of the toxin, and the method of exposure, but may include:
  • Signs and symptoms usually begin within 4-6 hours of being exposed to the toxin. Death can occur between 36 and 72 hours of exposure.
  • The resulting symptoms depend upon the amount of the toxin and the method by which the individual was exposed.
  • There are no available antidotes or vaccines for ricin poisoning.
  • It has no treatment or preventive vaccine.
  • It is easily and inexpensively produced, highly toxic, and is stable in aerosolized form.
  • The use of this type of poison for terror attacks has been documented in both the US and other countries.

What Is Ricin, and How Is It Made?

Ricin is a protein derived from the beans of the castor plant (R communis). Castor beans are used in the production of castor oil, a brake and hydraulic fluid constituent. Ricin makes up 3% to 5% of the "waste mash" that is produced during this process. Separating out this protein is not difficult. It only requires chromatography, a common undergraduate chemistry skill.

How Much Ricin is Lethal?

A very small amount of ricin is lethal. In fact, it is far more potent than cyanide. An amount as small as a grain of table salt can be sufficient to kill an adult if it is ingested, inhaled, or injected. This poison acts by preventing cells from making proteins; if body cells cannot make protein, they eventually die. The person is killed when cells that compose vital organs cease to function.

How Long Does It Take for Ricin to Cause Symptoms of Poisoning?

Patient Comments

Symptoms depend on the route of exposure and the amount of absorption. Possible routes of absorption are respiratory (inhaled aerosol), gastrointestinal (GI [ingested]), and injected (percutaneous).

  • If exposed through inhaled aerosol, it will most likely affect numerous individuals simultaneously. In this case, a cluster of people would develop similar symptoms over a brief period, typically within 8 hours following inhalation. Such an occurrence would point to the possibility of an intentional act. People exposed to it may experience fever, nausea, and vomiting, a progressively severe cough, and congestion in the nose and the throat. Other symptoms associated with inhalation of ricin include difficulty breathing and tightness in the chest. With significant exposure to the poison, breathing difficulties occur within 12-24 hours. A chest X-ray may reveal excess fluid in the lungs.
  • If exposed by ingesting contaminated foods or beverages, symptoms may initially mimic food poisoning, usually within 6 hours after ingestion. People who ingested it may have abdominal pain, often accompanied by vomiting and diarrhea. Because of this, they may also become dehydrated. Although ingesting ricin is usually less toxic than exposure through inhalation, with significant amounts of the poison, which results in more severe symptoms, and possibly death. Dehydration is common. If the dose was sufficient and the disease has progressed, vomiting blood or passing bloody diarrhea or dark-colored tarry stools may occur.
  • People injected with ricin, either in pellet form or with it dissolved in a liquid, may experience pain and swelling at the injection site. They may experience other flu-like signs, such as nausea, vomiting, and body aches. More severe symptoms will occur later and a critical life-threatening syndrome will develop. The skin at the injection site is examined for swelling and redness. The affected area may feel painful. The skin is also examined for the possibility of a retained foreign object. The physical findings on the skin may occur prior to or at the time of other flu-like symptoms.

How Long Does It Take for Ricin Poisoning to Cause Death?

A person can die from ricin poisoning by injection in about 36 to 72 hours after exposure. The type of exposure also determines the speed, severity, and type of symptoms that will develop.

How Can I Tell If I've Been Poisoned by Ricin?

Diagnosing an aerosolized attack or a food and water contamination of this type of poisoning primarily depends on symptoms and the likelihood of such an exposure. In cases of an isolated ricin injection, diagnosis is extremely difficult. In addition, diagnostic testing is of limited value, because there are no definitive, widely available medical tests that can confirm exposure to the poison. Nonetheless, in the case of possible exposure, the patient will most likely undergo a complete physical examination by a doctor. Sophisticated diagnostic tests (not widely available) can identify ricin in the body up to 24 hours after exposure. Please see the section on signs and symptoms for information about early symptoms.

Medically Reviewed by a Doctor on 2/15/2017
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Ricin Poisoning - Symptoms

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What Is a Biological Terrorist Attack?

Biological weapons (agents) are poisonous compounds produced by microorganisms found in nature that can be used to kill or injure people, for example, bacteria, viruses, fungi, or toxins. These biological weapons can be used to kill one person or as a terrorist attack it can kill thousands of people depending on the transmission (inhalation, ingested, or skin and eye exposure), and the amount of exposure.


Read What Your Physician is Reading on Medscape

CBRNE - Ricin »

Ricin is a potent toxin that has potential to be used as an agent of biological warfare and as a weapon of mass destruction (WMD).

Read More on Medscape Reference »


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