Castor oil is made from the seeds of castor plants. The seeds are not suitable for human consumption as they contain the toxin ricin. The beans are harvested and processed to make castor oil which is used in various health remedies and cosmetics.

The main allergen in castor bean allergy is called Ric c 1. This is a 2S albumin protein. This group of proteins are involved in seed storage, plant growth and development.

Castor oil contains ricinoleic acid and is a common ingredient in lipsticks and lip care products. This has been known to cause contact allergic reactions.

Allergic cheilitis is the name given to swollen lips from a contact allergic reaction. This can be cause by castor oil in lipcare products.

Other food containing 2S albumin seed storage proteins are cashews, peanuts, brazil nuts, mustard seed, rapeseed, turnip, chickpeas, hazelnuts, pistachio, buckwheat, soya, sunflower seeds, walnuts, kiwi, castor beans and sesame seeds.

Please note that this food list is not exhaustive, the most up to date information is on the Cross Reactivity Tool.

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