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castor oil

Stimulant laxative · Laxative

Stimulant laxativeLaxativeATC A06AB05
CDSCO approvedATC A06AB05
EXCRETION
not curated
INTERACTIONS
none in our sources
PREGNANCY
not curated

Mechanism

Castor oil is hydrolyzed in the small bowel by lipases into glycerol and ricinoleic acid (the active agent). Ricinoleic acid acts primarily in the small intestine to stimulate secretion of fluid and electrolytes and speed intestinal transit.

Dosing

Adult
For laxative effect, as little as 4 mL. For cathartic effect, 15 to 60 mL.

Pharmacokinetics

Onset
1 to 3 h (when taken on an empty stomach)

Side effects

Serious
  • Potential toxic effects on intestinal epithelium and enteric neurons

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Sources: Goodman & Gilman 14e·Verified: 2026-05-10 · House clinical team