Is Castor Oil Plant Toxic to Cats?

Ricinus communis

The seeds of Ricinus communis contain ricin, one of the most toxic substances found in plants. A cat that chews a seed is at serious risk, and the plant self-seeds readily in UK gardens once established.

The leaves are less dangerous than the seeds, but 'less dangerous' is not safe. Because cats climb and investigate, the seed heads are the part that matters.

Which parts are dangerous

• seeds
• leaves

What to watch for in the UK

• Grown as a dramatic foliage plant in UK gardens and allotments.
• Self-seeds readily; seedlings appear the following spring.
• Seed heads drop to the ground, where a cat can find them.
• Wear gloves when removing it.

If your cat has already chewed it

1. Emergency vet immediately.
2. Say it may be the castor oil plant — that changes the assessment.
3. Take the seed or plant material with you.

Take a photo of the plant, and a cutting if you can do it safely — identification is half of the vet's decision. Out of hours, use your practice's emergency number. This page explains risk; it cannot diagnose your cat and it contains no home treatments.

If your cat has vomited after eating a plant, see the cat vomiting guide and, if there is blood, vomiting blood. For a general red-flag checklist, use sick cat symptoms. If the worry is food rather than a plant, the can cats eat guide covers 36 everyday foods.

Related plants

Browse the full UK plant checklist (72 plants).