# Plant Monograph: Castor Bean
**Name of plant:**
Castor bean
**Catch phrase (Carmina Gadelica or traditional invocation if available):**
**“The palm of healing, whose oil moves what is bound.”**
No Carmina Gadelica invocation specifically associated with castor bean has been identified. The plant has, however, an exceptionally long medicinal history, with castor preparations documented in ancient Egyptian medicine and subsequently throughout African, Asian and Mediterranean traditions.
**Family:**
Euphorbiaceae
**Genus and species:**
*Ricinus communis* L.
**Other names:**
* Castor bean
* Castor oil plant
* Castor
* Palma Christi
* Palm of Christ
* Castor-oil plant
* Wonder tree
* *Ricinus communis*
* Ricin plant
**Brief introduction:**
Castor bean is a fast-growing perennial shrub or small tree native to tropical Africa and now cultivated and naturalized throughout warm regions of the world. It has large, deeply lobed leaves and distinctive spiny fruit capsules containing mottled seeds.
The plant has an ancient medicinal history, particularly because its seeds yield **castor oil**, a distinctive vegetable oil rich in ricinoleic acid. Castor oil has traditionally been used as a laxative and externally as an emollient and massage oil.
The plant itself, however, is **highly poisonous**. The seeds contain ricin, a potent ribosome-inactivating toxin. Properly produced castor oil does not contain ricin because the toxin does not partition into the oil during processing.
**Traditional uses:**
* Castor oil traditionally used as a strong laxative.
* Castor oil applied externally to dry or irritated skin.
* Leaves historically used externally as poultices in various traditional medical systems.
* Castor preparations were traditionally used for muscular and joint discomfort.
* Various cultures used castor preparations in reproductive and obstetric traditions, although many of these historical applications lack modern evidence and some are unsafe.
**Historical use:**
* Castor bean was used medicinally in ancient Egypt, with evidence dating back to the Ebers Papyrus.
* Traditional African, Indian and Middle Eastern medicine used castor oil and other plant preparations for digestive and external complaints.
* Castor oil became an important nineteenth- and twentieth-century pharmaceutical laxative.
* The oil was widely used historically in household medicine and as a general-purpose purgative.
* The plant acquired the devotional name **Palma Christi**, or “Palm of Christ,” because of its distinctive palmate leaves and longstanding medicinal associations.
**Parts used and method of use:**
* Purified castor oil from the seeds.
* Leaves, traditionally used externally in some medical systems.
Used as:
* Oral castor oil as a short-term stimulant laxative.
* Castor oil applied externally as a skin-conditioning oil.
* Traditional leaf poultices or compresses.
* Pharmaceutical, cosmetic and industrial preparations of purified castor oil.
**Use in healing (modern herbal practice):**
* Short-term treatment of occasional constipation.
* External emollient and skin-conditioning preparation.
* Pharmaceutical excipient and vehicle for topical preparations.
* Investigated experimentally for anti-inflammatory and antimicrobial properties.
* Historically investigated and used for induction of labour, although this application is medically controversial and should not be undertaken without professional supervision.
The **medicinal plant material should not be confused with pharmaceutical-grade castor oil**. The seeds themselves are poisonous and are not a medicinal dose form. The European Medicines Agency recognizes properly prepared castor-oil medicines for short-term treatment of occasional constipation in adults.
**Pharmacology and biochemistry:**
* **Ricinoleic acid** — the principal fatty acid of castor oil and the major contributor to its laxative activity.
* **Ricin** — a highly toxic ribosome-inactivating protein concentrated in the seeds.
* **Ricinine** — a pyridone alkaloid found in the plant and seeds.
Mechanisms:
* Intestinal lipases release ricinoleic acid from castor oil; ricinoleic acid activates prostanoid receptors including EP3/EP4 and stimulates intestinal smooth-muscle activity.
* Ricinoleic acid increases intestinal propulsion and alters intestinal fluid and electrolyte handling, producing a stimulant-laxative effect.
* Ricin binds to cells and inhibits protein synthesis by damaging 28S ribosomal RNA, producing severe cellular toxicity.
**Overall profile:**
Castor bean is a **medicinally important but highly toxic plant**. Properly processed castor oil has a well-established short-term laxative action and extensive pharmaceutical and cosmetic applications. The intact seed and other unprocessed plant material must be regarded as poisonous because of ricin. The distinction between **castor oil and castor bean** is essential.
**Common dosage:**
* **Purified castor oil, oral laxative:** adults generally use approximately 15–60 mL as a single dose, according to the specific medicinal product's directions.
* **Castor oil capsules:** dose according to the standardized product label.
* **Topical castor oil:** applied as required to intact skin as an emollient.
* **Castor bean/whole seeds:** **NO medicinal dosage — do not ingest.**
Castor oil should be used only for short-term occasional constipation. EMA recommends that medicinal castor-oil preparations be used in adults and for no longer than one week without medical supervision.
**Safety factors (including side effects):**
* **Castor beans/seeds are poisonous because they contain ricin and must never be used as a home medicinal preparation.**
* Castor oil may cause nausea, vomiting, abdominal cramping and severe diarrhea.
* Do not use castor oil with intestinal obstruction, unexplained abdominal pain, inflammatory bowel disease, appendicitis or severe dehydration.
* Avoid medicinal use during pregnancy unless specifically directed by a qualified clinician; castor oil can stimulate intestinal and potentially uterine activity.
* Chronic or excessive laxative use may cause dehydration and electrolyte disturbances and should be avoided.
**First aid / adverse reaction response:**
* **Excessive diarrhea or vomiting:** stop castor oil and replace fluids/electrolytes; seek medical advice if significant.
* **Severe abdominal pain or persistent vomiting:** discontinue use and seek urgent medical assessment.
* **Suspected castor-bean ingestion:** **do not induce vomiting; contact a poison-control centre or emergency medical service immediately.**
* **Suspected ricin poisoning:** immediate emergency medical evaluation is required; treatment is supportive and there is no routinely available specific antidote.
* **Weakness, fainting, confusion or signs of severe dehydration after excessive laxative use:** seek urgent medical attention.
**Drug interactions:**
* Excessive castor-oil use can cause fluid and electrolyte depletion and may complicate treatment with medicines affected by electrolyte disturbances.
* Severe diarrhea may reduce absorption of orally administered medicines.
* Concurrent use with other stimulant laxatives may increase cramping, diarrhea and electrolyte loss.
* Patients taking important prescription medicines should avoid prolonged or unsupervised use of castor oil.
**Horticultural requirements:**
* **USDA / Canadian zone:** USDA zones approximately 9–11 as a perennial; commonly grown as a fast-growing annual ornamental in colder Canadian climates.
* **Soil pH:** Approximately 5.5–7.0.
* **Light requirements:** Full sun.
* **Moisture:** Moderate to moist, fertile soil with good drainage; established plants tolerate some dryness but grow best with regular moisture.
**Other notes (growth habit, harvest timing, etc.):**
* **Growth habit:** Very fast-growing shrub or small tree, potentially reaching several metres in warm climates. Large palmate leaves give the plant a tropical appearance.
* **Flowering/fruiting:** Flowers are produced in terminal clusters followed by distinctive spiny seed capsules.
* **Harvest timing:** Seeds mature within the capsules during the growing season; **seeds should not be harvested for home medicinal oil production because of the danger associated with ricin-containing seed material and processing residues.**
* **Habitat:** Tropical and subtropical regions, disturbed ground, river margins, roadsides and cultivated gardens.
* **Propagation/cultivation notes:** Easily propagated from seed in warm conditions. Requires warmth, sunlight and fertile soil. In frost-prone Canada it is generally cultivated as an annual ornamental.
**Sampling of clinical reports / studies:**
* **Clinical study:** Clinical evidence supports castor oil as an effective short-term stimulant laxative; the EMA considers its medicinal use for occasional constipation well established.
* **Pharmacological study:** Ricinoleic acid is responsible for the characteristic laxative action through effects on intestinal prostanoid receptors and smooth-muscle activity.
* **Phytochemical study:** Castor seeds contain triglycerides rich in ricinoleic acid as well as ricin, ricinine and allergenic proteins; properly processed castor oil is separated from the water-soluble ricin toxin.
* **Ethnobotanical evidence:** Castor has an exceptionally long history of medicinal use, including documented ancient Egyptian use and extensive traditions in Africa and Asia.
* **Overall assessment of evidence:** **Strong evidence for properly prepared castor oil as a short-term stimulant laxative; extensive historical and ethnobotanical evidence; significant toxicological evidence concerning the intact seed. Castor bean should be treated as a poisonous plant, while pharmaceutical-grade castor oil represents a distinct and carefully processed medicinal preparation.**
Educational Use Only: The information presented on this page is provided for educational, historical, and informational purposes only. ArdNemeton na Tuatha and Bhùth Draoi do not provide medical advice. Always consult your physician and pharmacist before using any herb, mushroom, supplement, or botanical product for medicinal purposes. Traditional uses described herein do not constitute medical claims.