Prune juice for chronic constipation in a randomised trial
What it found
In 84 people with chronic constipation, prune juice softened hard stools and eased complaints over 8 weeks.
It did not increase loose or watery stools.
What they found
Studies in people
Hard stools
In the prune juice group, the rate of hard and lumpy stools fell from the start and was lower than the placebo group after 3 weeks.
Normal stools
The rate of normal stools rose from the start in the prune juice group and was higher than the placebo group after 3 weeks.
Loose stools
The rate of loose and watery stools did not change significantly during the study.
Gut complaints
Constipation, hard stools, incomplete evacuation and flatulence scores fell at week 4 or 8 in the prune juice group. Constipation and hard stools scores were better than placebo at week 8.
Diarrhoea and urgency
Diarrhoea, loose stools and urgent need for defecation scores did not change significantly from the start.
Side effects
No adverse events or laboratory abnormalities of liver or kidney function were found in either group.
What the authors conclude
- They conclude that prune juice improved stool form and eased constipation complaints without abdominal discomfort in people with chronic constipation.
- They say their data support recommending natural food treatment as an alternative or complement to drugs.
- They suggest prune juice could be used continuously and safely by people with chronic constipation.
How it was done
Laxatives for chronic constipation can have side effects and may not work well enough. The authors wanted to test a natural food option, prune juice, in people with chronic constipation.
They ran a double-blind, randomised, placebo-controlled trial in Japanese people aged 20 to 75 with treatment-naive chronic constipation. 84 people were assigned to prune juice or a placebo matched for flavour, colour and taste, and took 54 g a day for 8 weeks. Stool form was recorded at each bowel movement and gut symptoms were scored at the start, 4 weeks and 8 weeks.
What it can’t tell you
- The trial lasted 8 weeks, so it cannot show what happens over longer periods.
- It tested one prune juice product at 54 g a day, so results may not apply to other amounts or types.
Who paid
- Conflicts
- Guarantor of the article: Hirotaka Yamamoto, PhD. Specific author contributions: T. Koyama and H.Y. designed and planned the study. T. Koyama and N.M. collected the data. K.N. performed statistical analysis. T. Koyama and H.Y. prepared the original draft. N.N. and T. Kawai supported editing of the original draft and critically revised the manuscript. All authors approved the final draft. Financial support: This study was partially funded by MIKI Corporation. Potential competing interests: This study was partially funded by MIKI Corporation. N. Nagata and K. Nishiura received a grant from MIKI Corporation. MIKI Corporation has outsourced some of this research to Oneness Support on a fee-for-service basis. N. Miura received a payment from Oneness Support. T. Koyama and H. Yamamoto are employees of MIKI Corporation. The sponsor had no control over the interpretation, writing, publication, or decisions about this work. The other authors declare no conflicts of interest. Ethics: This study was conducted in accordance with the Declaration of Helsinki. Human rights of the subjects were well protected, and the study was conducted with the approval of the institutional review boards of the Miura Clinic (approval number: R2001) and Tokyo Medical University (approval number: T2021-0243). Written informed consent was obtained from all subjects before their enrollment into the study. Clinical Trial Registration: This study was registered at ClinicalTrials.gov (https://www.umin.ac.jp/english/, UMIN 000041384).
- Authors work at
- Institute for Health Science, Japan; Tokyo Medical University, Japan; Fujita Health University Hospital, Japan
The paper
- Title
- Prune Juice Containing Sorbitol, Pectin, and Polyphenol Ameliorates Subjective Complaints and Hard Feces While Normalizing Stool in Chronic Constipation: A Randomized Placebo-Controlled Trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Koyama T, Nagata N, Nishiura K, Miura N, Kawai T, Yamamoto H (2022). Prune Juice Containing Sorbitol, Pectin, and Polyphenol Ameliorates Subjective Complaints and Hard Feces While Normalizing Stool in Chronic Constipation: A Randomized Placebo-Controlled Trial. The American journal of gastroenterology. doi:10.14309/ajg.0000000000001931Free full textPubMed 35971232DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error