What Is Ricin?

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. Ricin is very stable, therefore it is not susceptible to extreme conditions such as very hot or very cold temperatures.

Where Is Ricin Found and How Is It 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.

How Could I Be Exposed to Ricin?

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

People can be poisoned by breathing in ricin mist or powder or by ingesting poisoned food or water.

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

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

In 2003 and 2004, there were two cases where ricin was sent to political figures in the mail. Neither resulted in illness.

Signs and Symptoms of Ricin Exposure

The major symptoms of ricin poisoning depend on the route of exposure and the dose received.


Initial symptoms of ricin poisoning by inhalation may occur within 8 hours of exposure. Within a few hours of inhaling significant amounts of ricin, the likely symptoms would be respiratory distress (difficulty breathing), fever, cough, nausea, and tightness in the chest. Heavy sweating may follow as well as fluid building up in the lungs (pulmonary edema). This would make breathing even more difficult, and the skin might turn blue. Finally, low blood pressure and respiratory failure may occur, leading to death.


Following ingestion of ricin, initial symptoms may occur in less than 6 hours but usually are delayed for 1 to 3 days. If someone swallows a significant amount of ricin, he or she would develop vomiting and diarrhea that may become bloody. Severe dehydration may be the result, followed by low blood pressure. Other signs or symptoms may include hallucinations, seizures, and blood in the urine. Within several days, the person’s liver, spleen, and kidneys might stop working, and the person could die.

Skin and eye exposure

Ricin in the powder or mist form can cause redness and pain of the skin and the eyes.

Death from ricin poisoning could take place within 36 to 72 hours of exposure, depending on the route of exposure (inhalation, ingestion or injection) and the dose received. If death has not occurred in 3 to 5 days, the victim usually recovers.

How is Ricin Poisoning Treated?

Because no antidote exists for ricin, the most important factor is avoiding ricin exposure in the first place. If exposure cannot be avoided, the next most important factor is then getting ricin off or out of the body as quickly as possible.

Ricin poisoning is treated by giving victims supportive medical care to minimize the effects of poisoning.

What Can Be Done to Avoid Exposure?

While ricin could be used by a terrorist in a number of ways, the most attention has been given to exposure via the mail. The University community is encouraged to follow the University Mail Handling Guidelines when opening or processing mail.

All individuals handling bulk quantities of mail at Princeton University are required to attend training, per the University Mail Handling Policy.

What to Do if You Are Exposed to Ricin?

First, get fresh air by leaving the area where ricin was released. If the ricin was released outside, move away from the area where the ricin was released. If the ricin was released indoors, get out of the building.

Contact Public Safety at 911.

Depending on the situation, emergency responders may tell you to evacuate an area, or to “shelter in place” inside a building to avoid being exposed. Please see your building’s Emergency Action Plan for evacuation procedures, or visit the Emergency Guidelines for the Campus Community web site for more information.

Follow the advice of the emergency responders. In most cases, they will advise you to remove your clothing, rapidly wash your entire body with soap and water, and get medical care immediately. The emergency responders will either escort you to a shower or provide equipment for this decontamination.

Quickly remove clothing that may have ricin on it. Do not pull clothing over the head – rather clothing should be cut off of the body.

As quickly as possible, wash any ricin from your skin with large amounts of soap and water. If your eyes are burning or your vision is blurred, rinse your eyes with plain water for 10 to 15 minutes. If you wear contacts, remove them and put them with the contaminated clothing. DO NOT PUT CONTACTS BACK IN YOUR EYES. If you wear eyeglasses, wash them thoroughly with soap and water. You can wear your eyeglasses again after washing.

Do not overly handle contaminated clothing. Emergency personnel will arrange for disposal.

If someone has ingested ricin, to not induce vomiting or give fluids to drink.

With any type of exposure, contact Public Safety at 911.

For more information

The following web resource may be useful:
Centers for Disease Control Facts About Ricin