Ricin is a toxic protein that comes from castor plant seeds. Ricin poisoning isn’t a common condition. When it does happen, it’s usually from eating the seeds. Ricin does occasionally see use for criminal purposes, but that’s not common either. When ricin poisoning does happen, it’s extremely treatable, and most people survive.
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Ricin poisoning is an illness you get from the toxic effects of castor plant seeds. Processing those seeds is part of making castor oil. But those seeds also contain tiny amounts of ricin (pronounced “RY-sin”), a toxic protein. Chewing and swallowing castor seeds can release ricin, which may harm you.
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Symptoms of ricin poisoning vary depending on how the toxin enters your body. And the more toxin involved, the worse the symptoms. You may notice signs and symptoms of poisoning begin within four to 12 hours after exposure. But in some cases, it can take days for symptoms to appear.
There are three main ways ricin can enter your body:
If ricin doesn’t enter your body, it may only cause superficial irritation. Ricin doesn’t absorb through skin well, so this type of exposure isn’t usually dangerous. But ricin can absorb through mucus membranes like the linings in your nose and mouth and through your eyes.
Castor seeds have a shell on the outside that lets them pass through your digestive system intact. Chewing the seeds breaks that coat and creates a risk of ricin poisoning.
Symptoms can start about four to six hours after you ingest them. But some of the more serious symptoms may not appear for one to three days. The symptoms include:
Inhaling ricin causes symptoms that start about four to eight hours later. These symptoms include:
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Ricin that gets into your body via injection doesn’t cause symptoms immediately. It can take up to 12 hours for you to have them. The symptoms can include:
Ricin poisoning can happen in two main ways: ingesting the seeds or exposure to processed ricin. But neither of these are common.
Castor seeds aren’t difficult to find. Castor plant farming is common around the world because its oil has many uses, especially industrial ones. It also grows in the wild on every continent except Antarctica. And castor plants are often used ornamentally in the U.S. That’s a key way children can get to and accidentally ingest the seeds. There are also reports of people chewing castor seeds to attempt suicide.
The other main way for ricin poisoning to happen is because of criminal uses. One example is using ricin to poison someone individually. Ricin also has potential for terrorist use, and the U.S. Centers for Disease Control and Prevention (CDC) lists it as a potential bioweapon. But the CDC’s classification also notes that while it’s moderately easy to spread, ricin’s potential deadliness is low.
The most dangerous ricin poisoning complications usually don’t happen right away.
The main complication of ingesting ricin is organ failure. The organs this will most likely happen to are your:
If you inhale ricin, the severe complications start about 18 to 36 hours later. They include:
The main complications with injected ricin are:
No matter how ricin enters your body, death is possible if the affected dose is high enough and you don’t get proper medical care.
There are several tests that healthcare providers might use to diagnose ricin poisoning. Providers will ask questions about how your exposure happened. Lab tests, like blood and urine tests, may help with diagnosis. There are urine tests that can detect ricinine, a related toxin from the castor plant, but they aren’t usually available at most hospitals. Regional laboratories are usually the only places that can test for ricinine.
Most treatments for ricin poisoning are supportive. They can include:
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If providers think or confirm ricin poisoning, they’ll want you to stay in the hospital for at least a few days. That way, they can treat you immediately if you have any of the more dangerous delayed symptoms or complications.
The best source of information about treatments for your situation is your healthcare provider. The information they provide will be the most relevant to your specific case.
The only way to prevent ricin poisoning is to not ingest the seeds. If you have pets or children, you may want to remove any existing castor plants or avoid planting them. Children shouldn’t play around castor plants without supervision.
Researchers are trying to find a vaccine against ricin. Because ricin is a protein, your body’s immune system can learn to defend against it. But this research still has a way to go before the vaccine becomes a reality.
If you have ricin poisoning, getting emergency medical care quickly is the best way to help yourself. But there are other things you may need to do depending on how the poisoning happened. If you think your exposure was from ingestion, call 911 (or your local emergency services number) or go to the nearest emergency room.
If you think your exposure was inhaled, like from ricin powder, you should do the following:
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No, there’s no cure for ricin poisoning yet. There is ongoing research looking for one, but it isn’t complete.
Yes, ricin poisoning is survivable. With proper care, about 98% of people who ingest ricin survive. There’s very little data about survival from inhaling or injection because it’s so rare for these to happen.
No, castor oil doesn’t contain ricin after proper processing.
Castor oil has U.S. Food and Drug Administration (FDA) approval for use as a laxative (though that use isn’t common because there are several better alternatives). There’s evidence of medicinal use of the castor plant going back thousands of years. But ancient writings also show people knew the seeds were toxic and used them carefully back then. Today, castor oil also occasionally makes the rounds on social media as a potential home remedy or miracle treatment. But experts caution that many of the touted benefits are just hype.
You might be worried about ricin poisoning because of something you saw online or read in the news. But ricin poisoning isn’t common. Avoiding the castor plant, either in the wild or around your home garden, can reduce your odds of any exposure. If you think you were exposed to ricin, get medical care right away. Fast diagnosis and treatment can make a big difference.
Last reviewed on 02/05/2025.
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