Castor oil is used all over the world for a whole variety of ailments, but very few people realize that the plant it comes from is highly toxic, containing as it does the albumin ricin. If you have a castor bean plant in your garden, grown for ornamental purposes you should treat it carefully and wear protective gloves and long sleeves when you prune it. It is cultivated for its flowers which are very pretty red ones, and its long-leaves foliage which looks a little like a hand (although not as much as the fingered citron fruit does).
It is believed to have originated in Africa, but it is mentioned in ancient Sanskrit writings and grows extensively in the Indian subcontinent in both its wild and cultivated state. It has become naturalized in the southern states of the US and also grows and is cultivated for its oil in countries such as Morocco, Brazil, Taiwan and the US.
Warm castor oil can be applied to the bridge of the nose to ease congestion and is useful to rub into dry, coarse skin. It is a strong purgative if taken internally, but is not one that is to be recommended. There are more effective ways of preventing constipation, such as eating bananas. They are a lot more pleasant-tasting and cure the disease and not just the symptoms.
The seeds from the castor plant are made into oil which is used not only in medicinal preparations, but also for industrial and agricultural use. The stems from the plant can be made into paper and wallboard, and the cake or meal left over from the oil-extraction process can now be fed safely to animals as there is a way of detoxifying it.
Because the sap from all parts of the plant is so highly toxic, it has been used as a poison just like the aak plant. It is said that 20 seeds or beans will kill a person, although it takes 80 or so to kill a rooster or a duck, but only 4 to kill a rabbit. (Please don’t try this as the experiment might well backfire.) However it acts as a counter-irritant to the stings of scorpions.
As a member of the spurge or Euphorbiceaea family of plants it is related to the cassava or manioc as well as to Dog's Mercury and French mercury, both of which should not be used as herbal remedies..
Apart from the oil used in medicine traditionally the leaves are applied to the forehead to relieve a headache, and hot applied to skin irritations in poultice form, and to ease pain and swellings. The hot leaves are also used to ease the pain of arthritis, gout, rheumatism and other inflammations and scientists have concurred that they do have anti-inflammatory properties, as does an ethanolic extract of the root bark which also has antihistamine properties.
In Ayurvedic medicine the leaves or pulp from the beans are applied hot to the abdomen to stop flatulence, while the oil is used for eye problems including conjunctivitis (red eye).The oil is also used for dry skin and internally is given for headaches, tremors, arthritis, sciatica and various other ailments mixed with guggul (Indian Bdellium or false myrrh). The juice of the leaves mixed with gur or jaggery is used for hepatitis and a decoction of the roots with Indian Bdellium is used for arthritis and rheumatism.
The plant was known to the ancient Greeks, as it was Herodotus the so-called Father of History who wrote that it was called kiki and used by the ancient Egyptians as an unguent and oil for lamps and the seeds have been found in the tombs of the pharaohs. Dioscorides writing his Materia Medica in the 1st century AD knew about the castor bean plant, saying that it was not good as food but that the seeds were good in external medicinal preparations. Pliny agreed, writing that the seeds were extremely purgative (they are actually less so than jamalgota, however).
Gerard writing in Britain in his Herball in the 16th century calls it “ricinus” or “kik” and says that the oil “Oleum cicinum” was good for skin diseases. It was used throughout Europe in the Middle Ages and was used to expel internal worms when all else failed. Combined with citron it has been used as a skin ointment for leprosy. The Latin name Ricinus means tic, of the sort that feed off dogs’ blood and this was probably because of the shape of the markings on the white seeds or beans. Kiki is still cultivated in Greece under the same name as that given to the plant by the ancient Greeks.
While the oil, bought over the counter can be very beneficial for a number of problems, but it is best not to attempt to make your own preparations from any part of the plant as it is highly toxic, with ricinoleic acid being the major compound in all parts of the plant.