When consumed orally—in a dose of as little as one-half tablespoon—castor oil can be effective for constipation. “It is usually taken during the day because, once swallowed, it works quickly,” explains Dr. Cryer. “It is generally safe for short-term use. In adults over 60, castor oil, if used for a long time, can make bowel problems worse by causing diarrhea.”
While taking castor oil by mouth can be safe in small quantities, sometimes it can cause nausea, cramping, abdominal pain, bloating, or interactions with other medications, according to Janese Laster, MD, a gastroenterologist in private practice in Washington, DC. Additionally, castor oil can reduce the amount of potassium in your body when ingested. “It should not be used long-term,” she says. “If a patient has long-term, chronic constipation, they should be evaluated by a physician.”
What about castor oil packs? Are those effective?
Castor oil is also commonly used in “castor oil packs,” which are typically pieces of wool that are doused in castor oil and placed over your liver for hours, or overnight. But there’s not much research behind the concept: “There is a small study from Turkey that used castor oil packs—applied over a large area of the skin—in nursing home patients with long-term constipation that found no effect on the number of bowel movements or amount of feces,” explains David Clarke, MD, a double-board certified internal medicine physician and gastroenterologist and president of the Psychophysiologic Disorders Association. “However, there was a decrease in the feces consistency score [bowel movements were not as hard], in straining during defecation, and in the feeling of complete evacuation after a bowel movement.” But there was no control group in the study, so, as Dr. Clarke explains, these reported benefits might easily have been due to the placebo effect and not the castor oil pack.
Who should not use castor oil in or on their body?
Because of castor oil’s effect on lowering the body’s potassium levels, patients taking diuretics should avoid it. Additionally, medications that lower body potassium levels by increasing potassium excretion into the urine should also be avoided when taking castor oil orally, advises Dr. Cryer.
If there is a medical reason for constipation (such as partial obstruction of the bowel due to a tumor, scar tissue, or inflammation) castor oil can actually worsen symptoms from these conditions, according to Dr. Clarke. And, as Dr. Rao explains, there are more effective laxatives on the market that are safer, like bulk-forming fiber laxatives or stool softeners, so castor oil should not be a first-line treatment option.