A castor oil plant is a shrub native to the Mediterranean region of the world. This plant has been cultivated for ornamental and medicinal regions since Ancient Egyptian times, as castor seeds found in the tombs of notable Egyptians testify. As the name of the plant suggests, castor oil is produced from the seeds and this product is available at health food stores in addition to being found compounded in a number of different products.
This flowering plant has palmate serrated leaves, varying in color from a dark and glossy green to a dull red. The flowers grow in upright spikes, later developing into seeds known as castor beans, covered by a spiky outer coating. Castor beans are not true beans, as these plants are not members of the bean family, but they superficially resemble beans. Seeds from the castor oil plant are sometimes used as beads in jewelry. A similar plant known as the false castor oil plant looks similar, but does not have the same properties.
Ricins communis, as it is formally known, grows well in the United States in USDA zones nine through 11. It prefers full sun to part shade and well drained soil. Because the castor oil plant can grow very rapidly and produce large foliage, it is advisable to plant it in an area where overshading of smaller plants is not a concern. Gardeners may also want to avoid the castor oil plant if they have pets or toddlers, due to concerns about the toxicity of the seeds; curious animals and children may chew the seeds or pods and become very sick.
In their natural form, castor seeds are toxic. They contain a highly potent toxin known as ricin. Consuming a few seeds can have very deleterious effects and can sometimes be deadly. However, if the seeds are cold pressed to extract the oil, it is possible to generate a product safe for human consumption. The ricin is released by heat, and as along as the beans are not heated during processing, it will remain trapped inside.
Castor oil has historically been used as a purgative. While it is safe to consume, it can irritate the intestines and may act to resolve constipation. It was also applied topically to the skin by some cultures. Today, castor oil is used in food processing in some regions, particularly in the development of food coatings. It is used in trace amounts and should not cause irritation to people who consume these products. Castor oil can also be used in the production of fuels.