Text Size

Site Search powered by Ajax

Castor Oil

Castor Oil

Botanical Description / Habitat

Ricinus communis


Euphorbiaceae (Spurge family e.g. poinsettias and rubber trees.)

Common Names

Castor oil
Palma Christi


Native to the West Indies.

A common annual ornamental, naturalized to temperate regions of the contiguous USA.


The name "ricinus" (L. insect) indicates that the seeds resemble some beetles or dog tick.

The castor bean has large leaves (associated with Palm Sunday); bean-shaped seeds, called castor beans; orange flowers; and spiny fruit.

The flowers develop into spiny capsules, containing 3 seeds. As the capsules dry, they explode to scatter the beans.

Medicinal Parts


Historical Properties & Uses

The Egyptians used castor oil for their lamps and ingested it with beer as a purgative, a use that has prevailed to modern times.

Lipstick will generally contain 30-40% castor oil.

As a skin emollient, non-comedogenicity is castor oil's least understood or appreciated benefit. Comedogens are defined as cosmetics or cosmetic ingredients that exacerbate or contribute to acne and are an important factor for dermatologists and consumers alike. To overcome this growing concern, cosmetic manufacturers are formulating products with noncomedogenic emollients. Castor oil and its derivatives are recognized as non-comedogens and emollients.

In recent times Edgar Cayce popularized its usage in skin diseases, for example: cancer and warts. He also specifies "castor oil packs".

It has even proven useful in inducing labor. (Anonymous, 1984 and Summers, 1997.)

It has also been recommended in the painless treatment of plantar warts. (Hogenauer, 1998.)

Method of Action

The oil has unique emollient properties.

Ricin is a protoplasmic poison, which has been evaluated in cancer treatment. (Lin, 1970)

Drug Interactions & Precautions

There are no known interactions.

The purgative action might eliminate a drug from the system, so castor oil should not be employed for this purpose with medication.

Safety Factors & Toxicity

Castor seeds are toxic, containing a highly poisonous protein, ricin, and a highly allergenic material identified as CB-LA. Neither is carried into the oil but remain in the by-product meal after extraction.

Ingestion of the whole bean may not be toxic, as it is indigestible unless chewed quite thoroughly. (Aplin)

Ricinoleic (or hydroxyoleic) acid, comprises 89-90% of the fatty acid composition of castor oil. The derivative, ricinine causes nausea, vomiting, hemorrhagic gastroenteritis, hepatic and renal damage, convulsions and death.

The castor bean can invoke an allergic reaction via inhalation, usually from occupational exposure e.g. in the holds of ships. Sensitization to castor bean seeds in occupational workers and people living close to oil processing factories has been acknowledged for some time. (Singh)

Castor oil has relatively high purity, (high for a naturally occurring material).

Castor oil is non-toxic, a renewable resource and biodegradable.

Extensive historical use of castor oil for internal consumption and topical application has established it as safe. As an added measure of safety an investigation was conducted by feed studies in a national toxicology program of the US Department of Health and Human Services (National Institutes of Health).

In 1990 the feed studies concluded there were "no significant adverse effects of castor oil administration in these Studies in rats or mice." Exposure to castor oil at dietary concentrations as high as 10% in 90-day studies did not affect survival or body weight gains.

Preparation & Administration

The oil is mostly used topically, these days.

The oil is obtained by cold expression and is widely available commercially. Some forms are pure cold processed while others may be contaminated with e.g. hexane.

Castor oil packs: pour the castor oil on an absorbent material, place this castor oil saturated material over the area and then cover it with a heating pad to heat the castor oil.

Note: This Herbal Preparation information is a summary of data from books and articles by various authors. It is not intended to replace the advice or attention of health care professionals.


Anonymous: Journal of Nurse- Midwifery 29(6):366-370, November-December 1984.

Aplin PJ & Eliseo T: Ingestion of castor oil plant seeds. Med J Aust, 1997 Sep, 167:5, 260-1.

Facts and Comparisons. The Lawrence Review of Natural Products. Nov, 1992.

Hogenauer, M: Castor Oil Dissolves Plantar Warts.Clinician Reviews, 1998, 8(6):160.)

International Castor Oil Association, Inc. Technical Bulletins. 1997.

Lin, J et al., Nature, 1970, 227:292.

Singh A et al., Specific IgE to castor bean (Ricinus communis) pollen in the sera of clinically sensitive patients to seeds. J Investig Allergol Clin Immunol, 1997 May, 7:3, 169-74.

Summers L: Methods of cervical ripening and labor induction. J Nurse Midwifery, 1997 Mar, 42:2, 71-85.