Rhubarb for Constipation: A Month-Long Trial and One-Week Guidance

The volunteers had infrequent stools and extensive exclusions

The registry for NCT05541991 specified adults 50 to 70 years old, passing one to three stools weekly, often hard or lumpy. It excluded severe constipation, irritable bowel syndrome, pelvic-floor dysfunction, diabetes and numerous medicines affecting the gut. Findings from that selected population cannot be assumed to cover those conditions.¹

The sponsor was Ortis. The registry was first posted in September 2022, after the recorded 2018 study completion, limiting its usefulness as evidence of a prospectively registered plan.¹

The 30-day trial measured benefit and loose stools

The 2022 paper² reports 42 randomized participants and 39 analyzed, mostly women, averaging 58. The tablets supplied 12.5 or 25 mg daily of anthraquinone derivatives expressed as rhein. These figures describe standardized constituents, not total root-powder weight.²

The higher dose improved stool frequency and consistency versus placebo; the lower dose improved consistency. 92% at the higher dose versus 23% with placebo reported improved transit speed. That was a perception rating, rather than a measured gut-transit-time result.²

More participants reported diarrhea or loose stools at the higher dose. Bloating and gas did not improve significantly. This small, month-long study cannot establish indefinite nightly safety.²

EMA’s current guidance covers short-term laxative use

The European Medicines Agency’s³ rhubarb-root summary covers Rheum palmatum, Rheum officinale and their hybrids. These preparations contain anthraquinones that stimulate bowel movements and alter water and salt handling in the bowel.³

Its stated use is short-term treatment of occasional constipation, for no longer than one week. Persistent or worsening constipation calls for a doctor or pharmacist. A trial lasting 30 days does not replace that guidance or an individual product’s leaflet.³

EMA lists stomach pain, cramping and diarrhea among possible effects, and water and salt imbalance with prolonged use. It says these medicines must not be used during pregnancy or breastfeeding, or with unexplained abdominal pain, bowel obstruction, inflammatory bowel disease or severe dehydration.³

These are European herbal-medicine conclusions. They do not establish approval or identical labeling for every supplement sold elsewhere.³

Ask about the ingredient and the duration

Bring the complete product name and label, your bowel record and your medicine list. Ask which type of laxative is being proposed, how long it is intended for and what should happen if symptoms persist.

NIDDK advises choosing a laxative with a healthcare professional and discussing possible medicine or supplement causes before changing them. If laxatives have been needed for a long time and bowel movements seem impossible without them, seek a supervised review. Pelvic-floor muscle problems may need biofeedback.⁴

The “What the Pharmacy Shelf Offers” section of Bloated by Dinner organizes constipation remedies by their action and intended use. Our constipation pharmacy guide examines the guideline evidence for commonly discussed options.