castor oil

Medically Reviewed on 4/13/2022

Generic Name: castor oil

Brand Names: Fleet Castor Oil, Emulsoil

Drug Class: Laxatives, Other

What is castor oil, and what is it used for?

Castor oil is an oil extracted from the seeds of the castor oil plant, Ricinus communis. Castor oil is an irritant/stimulant laxative available over-the-counter, taken orally for temporary relief of constipation and to clear the colon before colonoscopy. Castor oil also has softening and soothing effects and is topically used on the skin and hair. Castor oil is approved for use as a food additive and used in hard candies and it is also used in the manufacture of chemicals, soaps, coatings and lubricants.

Castor oil is made up of several fatty acids, but its laxative effects are from ricinoleic acid, the primary fatty acid, which gets released when intestinal enzymes break down castor oil. Ricinoleic acid acts as a surfactant, reduces absorption of fluid and electrolytes, and stimulates peristalsis, a series of intestinal muscle contractions that make bowel contents move.

In addition to its use as a laxative, castor oil has been traditionally used to promote uterine contractions, fat (lipid) metabolism, in wound healing because of its antimicrobial properties and for arthritis because of its anti-inflammatory properties.

There is, however, insufficient scientific research to support these uses and its use as a laxative is the only FDA-approved use. Castor seeds contain ricin, a toxic chemical, but castor oil itself is free of the toxin because the extraction process removes ricin. 


  • Do not use castor oil in the following circumstances:
    • Hypersensitivity to castor oil
    • Gastrointestinal obstruction or perforation
    • Fecal impaction
    • Symptoms of appendicitis or other abdominal conditions that require immediate surgical intervention (acute surgical abdomen)
    • Ulcerative colitis
    • Rectal fissures
  • Do not use during pregnancy, as it can cause premature labor

What are the side effects of castor oil?

Common side effects of castor oil include:

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug.

Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

What are the dosages of castor oil?

Oral Solution

  • 100%



  • 15-60 mL orally once

Colonic Evacuation

  • 15-60 mL orally once, 16 hours before colonoscopy procedure



  • Children below 2 years: 1-5 mL orally once
  • Children 2-12 years: 5-15 mL orally once
  • Children above 12 years: 15-60 mL orally once


Pancreatitis is inflammation of an organ in the abdomen called the pancreas. See Answer


What drugs interact with castor oil?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Castor oil may enhance the adverse effect of sodium sulfate

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • Avoid using castor oil during pregnancy; may cause premature uterine contractions
  • Castor oil use while breastfeeding is generally safe

What else should I know about castor oil?

  • Do not take castor oil at bedtime because castor oil has a rapid onset of action
  • Chill or take with milk, juice, or other beverages to improve palatability
  • Take castor oil on an empty stomach for quicker onset
  • Do not use castor oil for longer than one week; if bowel movement does not occur within a week, seek medical help
  • Do not take castor oil if you have abdominal pain, nausea, vomiting or rectal bleeding; seek medical help
  • Store castor oil out of reach of children


Castor oil is an oil extracted from the seeds of the castor oil plant, Ricinus communis, which is used as a laxative to temporarily relieve constipation and to clear the colon before colonoscopy. Common side effects of castor oil include abdominal cramping, diarrhea, nausea, vomiting, electrolyte disturbances, pelvic congestion syndrome, low blood pressure (hypotension), and dizziness. Do not use during pregnancy, as it can cause premature labor. Castor oil use while breastfeeding is generally safe.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 4/13/2022