LACTOLOGY FOUNDATION

Castor oil (ATC A06AB05) is a stimulant laxative derived from Ricinus communis, used for short‑term relief of constipation and bowel cleansing, but is generally not recommended during pregnancy and should be used with caution in breastfeeding because of limited data and potential for maternal and infant gastrointestinal effects.medpedia.framar+3

Overview and ATC Class

ATC class A06AB05 includes medicinal products whose active substance is castor oil used as a contact (stimulant) laxative for the gastrointestinal tract.ema.europa+1
Castor oil is a viscous triglyceride oil, rich in ricinoleic acid (~85–95%), obtained from the seeds of Ricinus communis; pharmaceutical preparations are refined and free of toxic protein ricin.youtubesciencedirect+1

Pharmacology and Toxicology

Orally, castor oil is hydrolyzed to ricinoleic acid, which activates receptors on intestinal epithelial and smooth muscle cells, leading to increased secretion and motility and a cathartic effect typically within 2–6 hours.sciencedirect+1youtube
Its strong stimulant action can cause pronounced diarrhea, abdominal cramping, nausea and vomiting; prolonged or high‑dose use may result in fluid and electrolyte disturbances and secondary renal strain.medpedia.framar+2

In therapeutic laxative doses, systemic toxicity from refined castor oil is low, but misuse (repeated high doses, use in vulnerable patients) increases risk of severe dehydration, hypotension, and exacerbation of underlying disease (e.g. renal impairment, inflammatory bowel disease).ema.europa+2
Castor beans themselves are highly toxic because of ricin and should not be used as medicinal preparations; toxicity of the seeds is distinct from that of purified pharmaceutical oil.ncbi.nlm.nih+1

Indications and Contraindications

Castor oil laxatives are indicated for short‑term treatment of occasional constipation and bowel cleansing (lavage) before diagnostic procedures when stimulant action is desired.sciencedirect+2
They should not be used for chronic constipation management because of the risk of dependence, colonic atony and electrolyte imbalance.medpedia.framar+2

Contraindications include: suspected or known intestinal obstruction, acute surgical abdominal conditions, inflammatory bowel diseases, severe dehydration, significant renal disease, uterine or gastrointestinal bleeding, and known hypersensitivity to castor oil.ema.europa+1
Use is contraindicated or strongly discouraged in pregnancy due to uterotonic and labor‑inducing effects and frequent maternal nausea; regulatory guidance advises against use during pregnancy and breastfeeding.pmc.ncbi.nlm.nih+3

Adverse Effects and Drug Interactions

Common adverse effects are abdominal pain, cramping, nausea, vomiting and intense diarrhea, which may be prolonged in sensitive patients.sciencedirect+2
Serious adverse outcomes include severe fluid and electrolyte loss (hypokalemia, hyponatremia), orthostatic hypotension, and, rarely, paralytic ileus or aspiration risk in newborns if administered inappropriately.drugs+2

Castor oil can impair absorption of fat‑soluble vitamins (A, D, E, K) and other lipophilic drugs because of its strong laxative effect and shortened intestinal transit.drugs+1
It may alter the effect of potassium‑sparing diuretics and other medicines whose efficacy depends on stable electrolyte balance; careful monitoring is advised when co‑administered.drugs+1

Dosage and Administration

For adults, typical oral doses are 20–30 g (approximately 1–2 tablespoons) taken once, usually on an empty stomach, with onset of effect in a few hours; repeated daily use is discouraged.medpedia.framar+1
Herbal medicinal product assessments recommend limiting use to short periods (generally ≤1 week) without medical supervision, and avoiding pediatric use.ema.europa+1

Lactation Safety (Toxico‑lactological Profile)

No robust pharmacokinetic data exist on the excretion of ricinoleic acid or other castor oil components into human breast milk after oral intake.journals.sagepub
Expert reviews describe castor oil as a strong stimulant cathartic and note the absence of direct milk‑level data, recommending caution because maternal diarrhea and fluid loss could indirectly affect milk production and maternal well‑being.journals.sagepub+1

Some lactation reference systems (e.g. certain compatibility lists and e‑lactation type assessments) classify castor oil as compatible or low‑risk when used appropriately, but emphasize the need for follow‑up and avoidance of routine oral use due to possible gastrointestinal effects in mother and infant.e-lactation+1
Regulatory herbal monographs in Europe state that castor oil medicines should not be used during breastfeeding, reflecting a precautionary stance in the absence of solid safety data.ema.europa

Topical use (for skin or hair) is generally considered low risk in breastfeeding, since systemic absorption from intact skin is minimal and significant transfer into milk is unlikely; however, application on or near the breast should be avoided to prevent direct ingestion by the infant and to reduce the risk of local irritation.mommed+2
Castor oil compresses or packs sometimes used for localized inflammatory conditions in breastfeeding parents are typically applied away from the nipple, for limited durations, with subsequent washing of the skin; these practices aim to minimize infant exposure and are based on empirical rather than high‑quality clinical evidence.nurturebynatureibclc+1

Given the lack of quantitative data, internal (oral) use of castor oil during lactation should be reserved for situations where safer laxatives are unsuitable and after individualized risk–benefit assessment; alternative laxatives with better‑documented lactation safety are usually preferred.journals.sagepub+1
In all cases, monitoring for maternal diarrhea, excessive fluid loss, and any change in infant stool patterns or irritability is advisable when castor oil is used by breastfeeding women.mommed+1

Clinical Recommendations in Pregnancy and Breastfeeding

In pregnancy, castor oil has historically been used to induce labor, but clinical data show high rates of maternal nausea and insufficient evidence of benefit; current guidance generally advises against its use for labor induction outside of controlled medical settings.pmc.ncbi.nlm.nih+1
Because of its uterotonic potential and the precautionary regulatory position, castor oil laxatives are classified as unsuitable in pregnancy except under explicit specialist supervision for clearly defined indications.drugs+2

For breastfeeding women with constipation, non‑pharmacological measures (dietary fiber, hydration, physical activity) and laxatives with established lactation safety profiles (e.g. certain osmotic agents or bulk‑forming preparations) should be preferred over castor oil.journals.sagepub+1
Topical cosmetic use of castor oil (hair and skin products) may be acceptable when limited, avoiding breast skin and ensuring removal of residues before nursing, but mothers should be informed about the lack of definitive safety studies.e-lactation+1