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Castor bean: toxicity, first aid and care

Castor bean (Ricinus communis): severe for cats, severe for dogs, severe for small children. The toxic principle, the signs, what to do, and how to grow it.

Cats: SevereDogs: SevereChildren: SevereEmergency risk

Also sold as: Castor oil plant, riitsinus.

This is a reference table, not a diagnosis and not veterinary or medical advice. It cannot tell you how much of a plant matters for a particular child or a particular animal — that depends on body weight, on the part eaten and on how long ago. If a person or an animal has eaten part of a plant, phone the poison information centre or a clinician; do not wait for symptoms, and do not make anyone vomit unless you are told to.

What is in it

Toxic principle: Ricin (in the seed) — Alkaloids and other systemic poisons.

Ricin is a protein that shuts down the ribosome, so an affected cell simply stops making protein and dies. It sits in the seed — the glossy mottled bean that looks like an engorged tick — and not in the pressed oil, which is heat-treated. The seed coat matters more than people expect: swallowed whole, seeds often pass intact, and the serious cases involve seeds that were chewed.

What it looks like when it goes wrong

Delayed by hours: burning in the mouth and throat, then severe vomiting and bloody diarrhoea, dehydration and abdominal pain, followed over days by liver and kidney injury.

What to do

Any chewed seed is an emergency call to a poison centre or a veterinary clinic, whatever the number involved, and the absence of early symptoms is not reassurance. There is no antidote; care is supportive and starts with fluids.

Anywhere in the European Union, 112 reaches emergency services and can put you through. Lithuania's poison information bureau (Apsinuodijimų kontrolės ir informacijos biuras) publishes its own round-the-clock line; if you do not have it to hand, use 112. For an animal, your own veterinary clinic or its out-of-hours service is the first call — human poison centres do not advise on animals in every country.

How to grow it

Sold in the region as a dramatic bronze-leaved dot plant for large containers and hot borders, raised from seed each spring on a windowsill. If you grow it with children or animals around, the workable compromise is to cut the flower spikes off before they set seed — the foliage is the reason to grow it, the seed is the reason not to.

What it gets confused with

Castor oil in the bathroom cabinet is not a hazard and does not contain ricin; the association confuses people in both directions. The seeds are the entire risk, and they are attractive: they are polished, patterned and bead-like, and have been strung as jewellery, which is a documented poisoning route.

A plant that is not on the toxic lists

If you are deciding what to keep in a home with a cat, a dog or a small child, this one fills a similar role and is not flagged by the veterinary services.

Others that work the same way

Alkaloids and other systemic poisons — these behave alike, and what you would do about them is alike too.

Source: Royal Horticultural Society — potentially harmful garden plants · checked 2026-09-06

Care guidance is standard horticultural practice for a cool-temperate northern climate. Poison-centre numbers are listed on the hub page and are worth confirming against your own country's health service.

Frequently asked questions

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