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Ricinus
Toxic🐾Ricinus communis · (Ricinus communis)
Spurge family (Euphorbiaceae)
Description
Large, hand-shaped lobed leaves and spiny seed capsules holding strikingly mottled, bean-like seeds make this warm-climate member of the spurge family (Euphorbiaceae) easy to recognise. Cold-pressing the harvested seeds yields pure castor oil, rich in ricinoleic acid, which has traditionally been used both internally and externally. IMPORTANT: the whole, unprocessed seeds contain the highly toxic lectin ricin and are extremely dangerous — as few as a handful of chewed seeds can be fatal to humans and animals. Cold-pressed, pharmaceutical-grade castor oil, by contrast, is considered free of ricin, since the toxin is water-soluble and remains in the press cake. Seeds and any uncrushed plant material must be kept strictly away from children and pets; if ingestion is suspected, contact poison control immediately.
CONTRAINDICATED during pregnancy
Whole castor seeds are strictly forbidden during pregnancy — ricin poisoning and severe volume loss through diarrhoea endanger mother and child. Pure castor oil as a laxative is also only to be used under medical supervision during pregnancy (e.g. for term labour induction by midwife/obstetrician), not for self-medication, as it can trigger uterine contractions.
CONTRAINDICATED during breastfeeding
Whole seeds and plant material are strictly contraindicated during lactation. Small amounts of pure, pharmaceutical-grade castor oil are considered compatible with lactation but should be used only on medical indication due to the risk of diarrhoea in the infant.
CONTRAINDICATED for children
Castor seeds are the most common cause of severe plant poisoning in children in the Mediterranean region — the colourfully patterned, bean-like seeds are visually attractive and as few as 1–2 chewed seeds can be lethal. In suspected seed ingestion: IMMEDIATELY call emergency services and poison control. Castor oil as a laxative is no longer used in paediatrics due to its unpleasant effect and risk of cramping; gentler alternatives (macrogol, lactulose) are standard.
Critical drug interactions with:
Andere Laxanzien (Bisacodyl, Sennoside, Macrogol)
External application of castor oil for dry skin, eczema, psoriasis and scalp dandruff. The historical epithet Palma Christi ('Hand of Christ') refers to the folk-medicinal reputation of healing wounds and alleviating ailments. Modern: cosmetic skincare, eyebrow and eyelash care; in dermatological folk medicine also for occupational eczema.
Preparation & dosage
Folk medicinal application of castor oil packs on the abdomen and liver as a naturopathic detoxification and anti-inflammatory practice, popularised by US healer Edgar Cayce. Scientific evidence is lacking; the application is generally considered skin-friendly. Seed powder was also applied locally to abscesses and skin infections.
Preparation & dosage
Sources: [3]
Folk medicinal rubbing with castor oil for joint pain, osteoarthritis and rheumatic complaints. In the Ayurvedic tradition, Eranda oil is massaged warm; ricinoleic acid acts mildly irritating and circulation-promoting on the skin. Antimicrobial activity against bacteria and fungi is plausible, but clinical evidence for the rheumatological indication is weak.
Preparation & dosage
Industrial and technical use of castor oil (no medicinal use): high-grade lubricant for high-performance engines (rotary engines of WWI aircraft, classic racing cars — 'Castrol R'), component in biodiesel, feedstock for sebacic acid and nylon-11, sulphonated 'Turkey Red Oil' as historical detergent. Polyglycerol polyricinoleate (PGPR, E476) is an emulsifier approved in chocolate manufacturing.
Preparation & dosage
Historical documentation only — do NOT use
These internal applications are historically documented. This plant is highly toxic — self-treatment can cause severe poisoning or death. For documentation only, explicitly NOT a recommendation.
Castor oil (Oleum ricini), obtained by cold-pressing the seeds, has been documented as a laxative since the ancient Egyptian Ebers Papyrus (c. 1550 BC) and is today regarded as the most continuously used laxative in human history. Mechanism: in the small intestine, ricinoleic acid is released from the triglycerides; it irritates the intestinal mucosa and increases peristalsis. Onset of action 2–6 hours. Important: pressed oil is FREE of ricin — the water-soluble lectin remains in the press-cake; additionally the oil is heated above 80 °C which denatures ricin.
Preparation & dosage
Historical folk-obstetric use of castor oil for labour induction at term — the so-called 'labour cocktail' of castor oil, apricot juice, sparkling wine or a warm bath is still occasionally used in German-speaking midwifery circles. Pharmacological mechanism not clearly understood; a 2024 Cochrane-style review concludes that no high-quality evidence exists for cervical ripening or labour induction, but that nausea and diarrhoea occur regularly. Use only under obstetric supervision.
Preparation & dosage
Folk medicinal use of castor leaf decoctions for cough and respiratory complaints in India and West Africa. Leaves are considered only mildly toxic (the main toxin ricin is localised in the seeds), but the application is not recommended today due to an unclear active-substance profile. In Ayurvedic medicine ('Eranda'), a traditional component of polyherbal formulations.
Preparation & dosage
SEEDS EXTREMELY TOXIC (ricin) — OIL SAFE at pharmaceutical quality. Important distinction: (1) Whole seeds contain the highly potent toxin ricin (1–5 % of seed protein), a type-2 ribosome-inactivating lectin. As few as 4–8 chewed seeds can kill an adult; oral LD approx. 1 mg/kg, by injection or inhalation a thousandfold more toxic (LD50 i.p. mouse approx. 22 μg/kg). Poisoning symptoms: burning sensation in mouth and throat, abdominal pain, bloody diarrhoea, vomiting, multi-organ failure with a latency of 2–36 hours, death within 3–5 days. No specific antidote — only supportive therapy. (2) Cold-pressed castor oil is FREE of ricin (water-soluble, remains in press-cake; additionally oil is heated above 80 °C for denaturation) and is approved worldwide as an OTC laxative. Ricin is listed as a Schedule-1 substance under the 1997 Chemical Weapons Convention and the 1972 Biological Weapons Convention — historically known for the 1978 Markov assassination in London (ricin pellet fired via a modified umbrella). Keep children and pets away from seeds and uncrushed plant. ASPCA classification (accessed 2026-08-10): toxic to dogs and cats.
Whole castor seeds are strictly forbidden during pregnancy — ricin poisoning and severe volume loss through diarrhoea endanger mother and child. Pure castor oil as a laxative is also only to be used under medical supervision during pregnancy (e.g. for term labour induction by midwife/obstetrician), not for self-medication, as it can trigger uterine contractions.
Whole seeds and plant material are strictly contraindicated during lactation. Small amounts of pure, pharmaceutical-grade castor oil are considered compatible with lactation but should be used only on medical indication due to the risk of diarrhoea in the infant.
Castor seeds are the most common cause of severe plant poisoning in children in the Mediterranean region — the colourfully patterned, bean-like seeds are visually attractive and as few as 1–2 chewed seeds can be lethal. In suspected seed ingestion: IMMEDIATELY call emergency services and poison control. Castor oil as a laxative is no longer used in paediatrics due to its unpleasant effect and risk of cramping; gentler alternatives (macrogol, lactulose) are standard.
Drug interactions
Andere Laxanzien (Bisacodyl, Sennoside, Macrogol)
Additive laxative effect with risk of severe diarrhoea, volume loss and hypokalaemia.
Herzglykoside (Digoxin, Digitoxin)
Castor oil-induced hypokalaemia increases the sensitivity of cardiac muscle to digitalis glycosides — risk of arrhythmia and AV block.
Kaliumverlust-Diuretika (Schleifendiuretika, Thiazide)
Additive hypokalaemia from diuretic plus castor oil diarrhoea; clinically relevant with prolonged use.
Lipidlösliche Medikamente (fettlösliche Vitamine A, D, E, K; orale Kontrazeptiva)
Castor oil can reduce absorption of fat-soluble substances by accelerating intestinal transit and forming oil emulsions — loss of efficacy possible.
Antikoagulanzien (Cumarine, Phenprocoumon, Warfarin)
Reduced vitamin K absorption due to castor oil-induced accelerated intestinal transit may potentiate the anticoagulant effect — INR fluctuations possible.
Contraindications
- Known allergy to castor protein (ricin-allergic reactions, anaphylactic shock documented)
- Ileus, mechanical bowel obstruction, acute abdomen (potentiation by castor oil as laxative)
- Acute inflammatory bowel disease (Crohn's flare-up, ulcerative colitis flare-up)
- Suspected appendicitis and unclear abdominal pain
- Severe dehydration and electrolyte disorders (hypokalaemia worsened by diarrhoea)
- Pregnancy (see above) — except controlled labour induction at term
- Children under 12 years for laxative indication (gentler alternatives available)
- Consumption of WHOLE SEEDS is absolutely prohibited — extreme poisoning risk through ricin
Harvested part: seeds
- Time of day:
- In dry weather as soon as the spiny seed capsules burst open — seeds are ejected explosively (ballistic dispersal).
- Drying:
- Seeds air-dried at room temperature, do NOT handle with bare hands; wear protective gloves and a mask when grinding or pressing (aerosol ricin extremely toxic on inhalation). For pharmaceutical oil extraction, cold pressing is followed by heating above 80 °C for ricin denaturation.
- Time of day:
- Morning after dew has dried — young, glossy leaves have the highest ricinine content
- Drying:
- Lay leaves loosely, dry at 30–40 °C in shade. Leaves are considered only mildly toxic (no ricin in leaves, only ricinine and other alkaloids), but protective gloves are recommended. Do not mix with seed material.
- Ricin (Typ-2 RIP-Lectin)OtherContent: 1-5 % des Samenproteins
Highly potent lectin toxin, ribosome-inactivating protein type 2; consists of two chains covalently linked by a disulfide bond: A chain (267 aa, N-glycoside hydrolase, blocks the 60S ribosomal subunit) and B chain (262 aa, galactose-binding lectin, enables cell entry). Oral LD in humans approx. 1 mg/kg; parenteral about three orders of magnitude more toxic. Water-soluble — remains in the press-cake, NOT in pressed oil. Listed as Schedule-1 substance under CWC 1997 and BWC 1972.
- Ricinin (Pyridon-Alkaloid)AlkaloidContent: 0.3-0.8 %
Pyridone alkaloid with a cyano substituent; detectable in all plant parts, especially in young leaves and seeds. Pharmacologically much less toxic than ricin; serves forensically as a biomarker for castor exposure (detection in urine of poisoning victims).
- Ricinolsäure (Ricinoleic acid)OtherContent: 85-92 % des Rizinusöls
Unusual hydroxylated unsaturated C18 fatty acid ((9Z,12R)-12-hydroxy-octadec-9-enoic acid); dominant component of castor oil (over 75 % as triglyceride ester). Laxative mechanism: cleavage in the small intestine by lipases → free acid → irritation of the intestinal mucosa, EP3 receptor activation, increased peristalsis. Also antimicrobial properties against bacteria, fungi and viruses.
- Ricinusagglutinin (RCA120)OtherContent: Spuren
Haemagglutinating lectin in the seed, structurally related to ricin (about 60 % sequence identity) but markedly less toxic. Binds like ricin to galactose residues and can agglutinate erythrocytes; important for laboratory chemistry and histochemical staining techniques.
- Nudiflorin und Ricinidin (Begleitalkaloide)AlkaloidContent: Spuren
Further pyridone alkaloids alongside ricinine; detected in small amounts in seeds and leaves; pharmacological significance minor.
- Ricinolein (Triglyceride der Ricinolsäure)OtherContent: über 75 % des fetten Öls
Triglycerides with ricinoleic acid as the dominant fatty acid; form the main component of cold-pressed castor oil. High viscosity and unusually good lubricating properties — hence industrially used as a high-performance lubricant.
- Phytinsäure / Phytat (Phosphorquelle)OtherContent: Hauptphosphorform im Samen (ca. 90 % des Samen-P)
Inositol hexaphosphate; main storage form of phosphorus in the seed. Pharmacologically insignificant, nutritionally an anti-nutrient (binds minerals).
- Flavonoide und PhenolsäurenFlavonoidContent: nicht quantifiziert
Accompanying substances in leaves and seed coats (kaempferol and quercetin glycosides, gallic acid derivatives); antioxidant active, pharmacologically of subordinate significance compared with ricin and ricinoleic acid.
- [4]MonographASPCA Animal Poison Control — African Wonder Tree (Ricinus communis)(accessed: 2026-08-10)
- [5]MonographCliniTox Giftpflanzen — Ricinus communis L.: sehr stark giftig +++ (Institut für Veterinärpharmakologie und -toxikologie, Universität Zürich)(accessed: 2026-08-10)
- [3]BookPlants For A Future — Ricinus communis(accessed: 2026-05-26)
- [1]WikipediaRicinus communis — Wikipedia (EN)(accessed: 2026-05-26)
- [2]WikipediaCastor oil — Wikipedia (EN)(accessed: 2026-05-26)