Drug reference
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
Drug interactions
12 additional unreviewed or low-confidence interactions hidden because their provenance or source detail is insufficient.
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Textbook-sourced·Sources: Goodman & Gilman 14e·Updated: 2026-05-10