Magnesium sulfate (Epsom salt) and constipation
What 5 graded rows on magnesium sulfate (epsom salt) agree on for constipation, and where they differ. Counted side by side, never averaged.
Consensus finder Rows from the Magnesium sulfate (Epsom salt) page, reviewed Oct 21, 2026 How it decides
What the rows agree on
Each block and row is one graded row from the Magnesium sulfate (Epsom salt) page, with its PubMed record.
Your question
Magnesium sulfate (Epsom salt) and constipation
5 rows · 653 peopleMostly an improvement: 4 of 5 rows, and most of the people. 1 had mixed results.
- BGrade B× 3
- CGrade C× 1
- DGrade D× 1
- Rows
- 5
- Trials
- 5
- People
- 653
What the rows share
From the rowsThe best-graded row, grade B, is a randomized trial of 244 people (2014) and found an improvement.
The rows run from 8 to 244 people, published from 2000 to 2019: 5 single studies.
The rows
4 improved · 1 mixed- BGrade BFunctional constipation in women (mineral water) · Improved
RCT · n 244 · 2014 · Women aged 18 to 60 with functional constipation (Rome III), recruited by 62 French general practitioners
0.5 L or 1 L/day of Hépar within 1.5 L/day of water · 4 weeks
At week 2, constipation was reduced in 37.5% with 1 L/day of Hépar vs 21.1% with low-mineral water (P = 0.013); 0.5 L/day gave 30.9% (P = 0.099). The 1 L group also had fewer hard stools and used less rescue medication. No serious adverse events.
Row on the Magnesium sulfate (Epsom salt) page · PubMed 24342746 (opens PubMed)
- BGrade BTreatment response in functional constipation (mineral water) · Improved
RCT · n 226 · 2019 · Outpatients with functional constipation in a multicentre trial
1 L/day within 1.5 L/day of water · 14 days
More people responded with Hépar than with low-mineral water at day 14 (50% vs 29%, P = 0.001), and mean time to response was shorter (6.4 vs 7.3 days). Safety results were good.
Row on the Magnesium sulfate (Epsom salt) page · PubMed 31170680 (opens PubMed)
- BGrade BBowel movements and stool consistency in functional constipation · Improved
RCT · n 75 · 2017 · Otherwise healthy adults with functional constipation (106 randomized; 75 in the 500 mL arms)
500 mL/day (300 mL arms stopped at interim analysis) · 6 weeks
Complete spontaneous bowel movements per week tended to rise more with the mineral water (one-sided p = 0.036); spontaneous bowel movements, stool consistency and constipation symptoms improved significantly versus placebo.
Row on the Magnesium sulfate (Epsom salt) page · PubMed 26582579 (opens PubMed)
- DGrade DGut transit speed and stool weight (oral laxative dose) · Improved
Crossover RCT · n 8 · 2000 · Healthy volunteers (four women, four men), aged about 21
One laxative dose per experiment · Four experiments
Magnesium sulfate accelerated duodenum-to-caecum transit and increased faecal weight and fat in every subject; with a meal it also raised peptide YY and inhibited gallbladder emptying.
Row on the Magnesium sulfate (Epsom salt) page · PubMed 10792122 (opens PubMed)
- CGrade CBowel movement frequency in functional constipation · Mixed
RCT · n 100 · 2016 · Adults with functional constipation (Rome III)
1 L/day (4 × 250 mL) · 6 weeks
At the primary 6-week endpoint there was no significant difference (p = 0.163). At 3 weeks, bowel movements rose by 2.02 a week with the mineral water vs 0.88 with tap water (p = 0.005).
Row on the Magnesium sulfate (Epsom salt) page · PubMed 27924798 (opens PubMed)