Rhubarb Extract for Hot Flashes: What the ERr 731 Trials Tested

The trials tested ERr 731, a specified Rheum rhaponticum root extract, including a 4 mg daily tablet. Cooking rhubarb, tea and unspecified powders cannot inherit those results.¹

Two short placebo trials reported benefits

The 2006 trial² included 109 perimenopausal women, with 54 assigned to ERr 731 and 55 to placebo for 12 weeks. The extract improved the overall menopause symptom score more than placebo. Differences in hot-flash number and severity were reported after four weeks. These were symptom outcomes, not evidence about preventing fractures, heart disease or dementia.²

The 2009 confirmation trial¹ randomized 112 women aged 45 to 55. Average Menopause Rating Scale scores fell from 27.0 to 12.4 with the extract, versus 27.0 to 24.0 with placebo. This 11-symptom scale runs from 0 to 44; it does not count daily flashes.¹

Nineteen women missed the planned final assessment; the main analysis carried earlier observations forward. Exclusions included breast or endometrial abnormalities and BMI above 30, limiting applicability.¹

Adverse events affected five women taking the extract and three taking placebo. One extract recipient had vertigo, weakness and headache considered possibly treatment-related. The trial was conducted for the manufacturer, which supplied the tablets; the paper states the manufacturer did not control its research content.¹

The 2026 paper reports earlier participants

A 2026 report describes the 112-participant trial conducted in 2004–2007, followed by 89 women taking the extract for 52 weeks. It reports additional outcomes, including headache/migraine, dizziness and tingling. It is not another independent trial recruiting a fresh group in 2026.³

Everyone in the follow-up received ERr 731, including former placebo recipients. Without a continuing placebo group, improvements over that year cannot establish how much was caused by treatment. Expectations, participant selection and symptoms changing over time remain possible explanations. The authors disclosed ownership or employment at Health Research Services, which funded the study.³

An earlier long-term report followed participants from the 109-woman trial. Eighty entered the first observational phase, and 51 continued into the second, reaching 96 weeks of follow-up. These are additional observations on an earlier trial population, with no continuing untreated comparison.⁴

When reading a product’s research list, check which papers describe new participants, which report other outcomes from the same trial, and which follow those women for longer.

The cancer study cannot answer the recurrence question

A 2025 German medical-record study⁵ compared 5,686 women prescribed ERr 731 with 17,058 matched women without such prescriptions. It found no statistically significant association with subsequent breast cancer diagnosis: hazard ratio 1.01, 95% confidence interval 0.81 to 1.26.⁵

That interval allows both lower and higher risk. The study excluded women with previous cancer, so it did not establish safety against recurrence or compatibility with cancer treatment.⁵

The records also missed purchases made without a prescription, leaving treatment duration uncertain. Lifestyle and other unmeasured differences could influence the comparison. Health Research Services funded the study and its publication; two authors were company employees. This is useful observational safety information, with those limitations, rather than a guarantee for an individual patient.⁵

Bring the product and one symptom target to the appointment

The 2023 US Menopause Society position statement did not recommend supplements or herbal remedies for hot flashes. It recommended several other nonhormonal approaches, including menopause-focused cognitive behavioral therapy, clinical hypnosis and certain prescription medicines. That recommendation evaluates the evidence as a whole; it does not erase the positive results above.⁶

The NHS⁷ advises discussing menopause treatment options with a doctor, nurse or pharmacist and notes that herbal remedies can interact with medicines. Bring the full ingredient label and your medicine list, particularly if cancer treatment is involved.⁷

The “Weeks Two to Four: One Useful Change” section of My Body Changed. Now What? asks you to record a start date, a reason for the change and a review date. For a clinician-agreed trial, choose the symptom that matters: flashes interrupting work, sweat-related awakenings or another stated concern. Record adverse effects and cost alongside any benefit. Our guide to hot-flash options without hormones covers other treatment discussions.

Have vaginal bleeding after menopause checked, even if it happens once or is only a small amount. The NHS⁸ advises medical assessment; a supplement’s study results should not be used to dismiss new bleeding.⁸