What To Know About Castor Bean Poisoning in Animals

Medically Reviewed by Amy Flowers, DVM on November 16, 2022
4 min read

Many household products contain castor beans or castor oil, and if your pets or livestock get a hold of them, the consequences could be devastating. Castor bean poisoning is dangerous for animals of all types, including dogs, cats, and even humans. 

The castor bean plant, Ricinus communis, is typically found in tropical or subtropical regions. It can reach a height of around three meters. It has a woody stem and long, serrated leaves up to 40 centimeters in length. The beans themselves grow in spiny capsules containing three beans each. Every part of the plant is toxic to animals, but especially the beans.

Though you’re unlikely to have raw castor beans or plant matter floating around your house, castor oil (made from the beans) is a common ingredient in many household items and is also sold on its own, serving a variety of functions. However, if your pets or livestock have a habit of getting into things they shouldn’t, it may be best to keep these castor-oil-based products well out of reach.

Sometimes, castor beans or other plant matter can be found in contaminated feed, specifically grain-based animal feeds, because the beans often go unnoticed among the other grains. Additionally, if you live in an area where the plant is native, your animals may find it in the wild and accidentally ingest the toxins it contains. In other places, it may even be intentionally cultivated to repel moles or other burrowing animals.

Castor oil is commonly used as a natural laxative. Though it may not be as effective as some pharmaceutical options, many people who prefer more natural remedies take it to relieve constipation. The ricinoleic acid found in castor oil will trigger receptors in the intestine that help move waste through the bowels.

Castor oil is also used due to its moisturizing properties. Like many oils, castor oil repels water, so spreading it across the surface of the skin prevents water from escaping and helps keep the skin hydrated. Again, this use of castor oil is most popular among people who prefer natural alternatives. In large quantities, castor oil can irritate the skin, so it is best used in moderation, preferably combined with other oils or natural ingredients to dilute it before application.

The moisturizing effect of castor oil also makes it popular in hair growth serums. Although it likely doesn’t cause the hair to grow any faster, it helps the hair retain moisture and fills in gaps within the cuticle, preventing and repairing damage. This makes it seem as though the hair is growing faster.

Other uses of castor oil, though not FDA-approved, can include inducing labor in pregnant people, killing bacteria and fungi (particularly on dentures), offering pain relief for headaches and menstrual cramping, and treating wounds.

Castor bean toxicity in animals can be very dangerous and unpleasant. The level of toxicity is often determined by how much is consumed, with castor bean and castor oil products proving most toxic to dogs, cats, and horses (although it is also dangerous to other livestock and even humans).

The harmful compound found in the plant is called ricin, which disrupts cellular function, eventually leading to cell death. Small amounts of ricin that are ingested (as opposed to being inhaled or absorbed through mucous membranes) are less likely to cause problems, though, since ricin is not as easily absorbed through the gastrointestinal system. Castor oil is also somewhat less toxic than raw castor beans or plant material because the process of heating the oil during production deactivates the ricin. That being said, it is still important to seek treatment right away if you think you or your pet may have eaten any part of the plant or products containing the oil.

The earliest symptoms of castor bean poisoning appear within a day or so of ingestion. Often, the first sign is vomiting or diarrhea, sometimes with blood in the stool. Depending on the severity of the poisoning, other symptoms may include neurological issues such as confusion or loss of coordination, loss of appetite, dehydration, trembling, unusual sweating, fever, and respiratory problems. If the poisoning is severe and goes untreated, the final stages typically include bloody diarrhea, seizures, and coma. At this stage, castor bean poisoning is often fatal

There is no cure for ricin poisoning, so the best way to treat it is to prevent it from happening in the first place. Even once the substance has been ingested, there are ways to keep it from being absorbed and mitigate some of the harm it might do.

Castor oil poisoning treatment is often best performed by a qualified veterinarian. The faster the treatment is administered, the less of the toxin will be absorbed and the less damage it will be able to do, so get your animal to a vet as quickly as possible. In most cases, a vet will pump the animal’s stomach full of intestinal protectants to prevent the toxic components from being absorbed. 

Emetics such as hydrogen peroxide or apomorphine may also be used to induce vomiting, followed by activated charcoal to absorb the remaining harmful compounds from the stomach before they can be processed in the intestines. If the animal is dehydrated due to vomiting or diarrhea caused by the toxin (or its treatment), the vet may also prescribe intravenous fluids.

In summary, castor bean poisoning can be very dangerous for animals. However, you can mitigate the damage by familiarizing yourself with the castor bean plant, paying attention to your animals’ health and behavior, and promptly seeking medical attention when it is needed.