Are blueberries good for constipation and IBS?

For constipation, nobody knows, because it has not been tested. We found no randomized trial of blueberries in people with constipation and no review that covers the question. For IBS there is one small trial. In a 6-week crossover study of 43 adults with irritable bowel syndrome or functional dyspepsia, 53 percent reported relevant relief of abdominal symptoms on freeze-dried blueberry powder against 30 percent on placebo. Stool form, the closest thing to a constipation result, did not differ significantly.

Unsettled. The one trial was small, used a powder supplied by the US Highbush Blueberry Council, and measured stools only as a secondary outcome in patients who were not selected for constipation. Its own authors wrote that effects of blueberries on stool consistency or gut motility had not been reported before.

What the trials found

The IBS trial gave 1.1 oz (30 g) a day of freeze-dried blueberry powder, which the authors equate to 6.3 oz (180 g) of fresh berries, against a placebo matched for sugars and energy. Overall, 23 of 43 patients reported moderate or significant relief on blueberry and 13 on placebo, a difference of 23 percentage points with a 95% interval from 1 to 46. The total score on the gut symptom questionnaire did not differ significantly. After 6 weeks, 2 patients had constipation-type stools on blueberry and 7 on placebo, 5 percent against 16 percent, with p at 0.10. That is a direction worth testing in a proper trial.

The best pooled evidence on fruit and constipation does not include blueberries. A 2022 meta-analysis of 11 randomized fruit trials in functional constipation found fruit raised stool frequency against placebo, with the effect driven by kiwifruit. Dates and orange juice did not reach significance, and no blueberry trial was in the pool.

A 12-week trial in older adults with overweight, using blueberry powder equal to 1.5 cups a day, found no overall change in gut microbiome composition or diversity. It did not measure bowel habits. Survey data from US adults link the highest intake of anthocyanidins, the pigments in blueberries, to lower odds of constipation after adjustment. That is an association, and these pigments track overall fruit and fiber intake.

The fiber itself is modest. A cup of raw blueberries, 150 g, has 3.6 g of dietary fiber and about 14 g of sugars, according to USDA food composition data.

Who should be careful

Not for everyone. If you are adding fiber for constipation, the US National Institute of Diabetes and Digestive and Kidney Diseases advises doing it a little at a time so your body can adjust. That applies to a sudden large bowl of berries or a scoop of berry powder as much as to anything else.

In the IBS trial no serious adverse events occurred over 6 weeks. That trial was too small to detect rare reactions. We looked for evidence on blueberry allergy and could not obtain it, so this page has no card on allergy, and the absence of one is not a sign that allergy never happens.

What expert bodies say

The NIDDK lists berries first among fiber-rich fruits to eat for constipation, alongside apples with the skin on, oranges and pears. That is general patient advice with no analysis of its own behind it, and the page was last reviewed in 2018. We found no agency position on blueberries specifically for constipation or IBS.

How we searched

What would change this answer

• A randomized trial of whole or powdered blueberries in people selected for constipation, with stool frequency as the main outcome. None exists.
• A larger repeat of the IBS trial, independent of industry funding, with stool form as a planned outcome.
• A head-to-head comparison with kiwifruit, the fruit with trial evidence, at a matched amount of fiber.

For what else the evidence says about blueberries, see the blueberries page.

Sources

1. ev-bbco-01 · Randomized controlled trial(s) · double-blind randomized placebo-controlled crossover trial, 6 weeks per period · n = 43
   Overall, 23 (53%) patients reported relevant moderate or significant symptom relief after blueberry treatment compared to 13 (30%) patients after placebo treatment (difference 23%, 95% CI [1 to 46%], p = 0.03).
   
   Who: adults with irritable bowel syndrome, functional dyspepsia or both (Rome IV), New Zealand
   Effect: responders 23 (53%) vs 13 (30%), difference 23% (95% CI 1 to 46%), p 0.03
   Certainty: Single small trial; powder supplied by the US Highbush Blueberry Council; total GSRS score did not differ significantly.
   Nutrients, 2023, 15(10):2396 (Blueberries improve abdominal symptoms, well-being and functioning in patients with functional gastrointestinal disorders) · checked 2026-10-07 · we read the fulltext
2. ev-bbco-02 · Randomized controlled trial(s) · double-blind randomized placebo-controlled crossover trial · n = 43
   Stool consistency: The numbers of patients with Bristol Stool Scale scores reflecting diarrhea, normal stool consistency, and constipation after 6 weeks treatment were 7 (16%), 34 (79%), and 2 (5%) with blueberry and 12 (28%), 24 (56%), and 7 (16%) with placebo treatment (p = 0.10).
   
   Who: adults with functional gastrointestinal disorders
   Effect: Bristol scale after 6 weeks: diarrhea 16% vs 28%, normal 79% vs 56%, constipation 5% vs 16% (blueberry vs placebo), p 0.10
   Certainty: Secondary outcome; patients were not selected for constipation, so the trial cannot answer the constipation question.
   Nutrients, 2023, 15(10):2396 (Blueberries improve abdominal symptoms, well-being and functioning in patients with functional gastrointestinal disorders) · checked 2026-10-07 · we read the fulltext
3. ev-bbco-03 · Randomized controlled trial(s) · double-blind randomized placebo-controlled crossover trial, methods · n = 43
   Blueberry: 30 g of highbush freeze-dried blueberry powder produced from equal proportions of Tifblue® and Rubel® varieties and equivalent to 180 g fresh blueberries (395 kcal/100 g, total carbohydrates 93 g/100 g, total fiber 24 g/100 g, fructose 30 g/100 g, glucose 30 g/100 g, total phenolics 32 mg/g analyzed by the Folin-Ciocalteu method, anthocyanins 11.4 mg/g).
   
   Who: adults with functional gastrointestinal disorders
   Effect: 30 g/day powder = 180 g fresh berries; powder 24 g fiber and 30 g fructose per 3.5 oz (100 g); placebo matched for sugars and energy
   Certainty: About 1.2 cups of fresh berries a day.
   Nutrients, 2023, 15(10):2396 (Blueberries improve abdominal symptoms, well-being and functioning in patients with functional gastrointestinal disorders) · checked 2026-10-07 · we read the fulltext
4. ev-bbco-04 · Randomized controlled trial(s) · double-blind randomized placebo-controlled crossover trial · n = 43
   No serious adverse events occurred during the study.
   
   Who: adults with functional gastrointestinal disorders
   Effect: no serious adverse events; rash with constipation and moderate nausea occurred on placebo only
   Certainty: 6 weeks of exposure; trial too small to detect rare reactions such as berry allergy.
   Nutrients, 2023, 15(10):2396 (Blueberries improve abdominal symptoms, well-being and functioning in patients with functional gastrointestinal disorders) · checked 2026-10-07 · we read the fulltext
5. ev-bbco-05 · Randomized controlled trial(s) · discussion of a randomized trial · n = —
   Effects of blueberry ingestion on stool consistency, GI motility or sensation have not been reported previously in either healthy or FGID subjects to the best of our knowledge.
   
   Who: healthy and FGID subjects (literature statement)
   Effect: no previous data on blueberries and stool consistency, motility or sensation
   Certainty: Matches our search: no constipation trial of blueberries found.
   Nutrients, 2023, 15(10):2396 (Blueberries improve abdominal symptoms, well-being and functioning in patients with functional gastrointestinal disorders) · checked 2026-10-07 · we read the fulltext
6. ev-bbco-06 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized and crossover trials · n = 11 RCTs
   Totally, fruits vs. placebo did significantly increase the stool frequency of patients with FC in the fixed-effect meta-analysis [MD = 0.26, 95% CI (0.22, 0.30), P < 0.00001, Figure 2].
   
   Who: people with functional constipation in randomized and crossover trials of fruit
   Effect: stool frequency MD 0.26 (95% CI 0.22 to 0.30), I2 0%; kiwifruit subgroup same estimate; palm date and orange juice not significant
   Certainty: Fruit tested were kiwifruit, dates, figs and orange juice; berries appear only in a microbiota subgroup, so it does not show blueberries work.
   Frontiers in Nutrition, 2022 (Effect of fruit intake on functional constipation: systematic review and meta-analysis) · checked 2026-10-07 · we read the fulltext
7. ev-bbco-07 · Observational data · cross-sectional analysis of a national survey · n = —
   Following multivariate adjustment, decreased odds of constipation could still be observed in the highest quartiles of anthocyanidins compared with those in the reference quartiles (p-value = 0.03).
   
   Who: US adults, NHANES 2007-2010, constipation by stool consistency or frequency
   Effect: highest vs reference quartile of anthocyanidins: lower odds of constipation (p 0.03); inverted U-shaped curve, falling above 0.92 mg/day
   Certainty: Anthocyanidins track overall fruit and fiber intake; odds ratio not given in the abstract.
   BMC Gastroenterol, 2024 · checked 2026-10-07 · we read the abstract
8. ev-bbco-08 · Position of an expert body · food composition database · n = —
   Blueberries, raw, FNDDS code 63203010, fdc_id 2709275: Fiber, total dietary 2.4 G per 100 g, 1 cup 150 g 3.6 G; Total Sugars 9.36 G per 100 g
   
   Who: USDA FNDDS food composition data
   Effect: per 3.5 oz (100 g): fiber 2.4 g, total sugars 9.36 g; per cup 150 g: fiber 3.6 g, sugars 14.0 g
   Certainty: Moderate fiber for a fruit; 3.6 g is about 13% of a 28 g daily target.
   USDA FNDDS, food code 63203010, Blueberries, raw (fdc_id 2709275) · checked 2026-10-07 · we read the dataset
9. ev-bbco-09 · Position of an expert body · agency patient guidance · n = —
   fruits, such as berries, apples with the skin on, oranges, and pears
   
   Who: people with constipation (US patient guidance)
   Effect: fruit examples: berries, apples with the skin on, oranges, pears; adults 22 to 34 g fiber a day
   Certainty: Patient advice without its own analysis; page last reviewed May 2018.
   NIDDK, Eating, Diet, & Nutrition for Constipation (NIH) · checked 2026-10-07 · we read the section
10. ev-bbco-10 · Position of an expert body · agency patient guidance · n = —
    Be sure to add fiber to your diet a little at a time so your body gets used to the change.
    
    Who: people with constipation (US patient guidance)
    Effect: gradual increase in fiber; drink water and other liquids with fiber
    Certainty: General fiber advice that applies to a sudden large intake of berries or berry powder.
    NIDDK, Eating, Diet, & Nutrition for Constipation (NIH) · checked 2026-10-07 · we read the section
11. ev-bbco-11 · Randomized controlled trial(s) · randomized placebo-controlled trial, 12 weeks · n = 55 randomized; 34 analyzed
    Comparing the baseline and endpoint results for the blueberry (n = 15) and placebo (n = 19) groups, there were no significant overall compositional differences or differences in the level of diversity in the fecal microbiome.
    
    Who: sedentary adults over 60 with BMI 25 to 32, weekly exercise classes
    Effect: no overall compositional or diversity differences; enrichment of Coriobacteriales incertae sedis (p 0.049)
    Certainty: Bowel habits were not measured.
    Nutrients, 2025 · checked 2026-10-07 · we read the abstract