Table 3.

Studies of the effect of magnesium sulfate-rich mineral waters in functional constipation.

Author, Year (Ref)	Design	Treatment	Comparator	Primary Endpoint	Outcome
Dupont et al. 2014 [32]	RCT, 244 participants (100% females), Rome III criteria	Hépar 0.5 or 1 L/day	Low mineral natural water (400 mg/L)	Response to the treatment: ≥4 stools/week or an increase of ≥2 stools per week AND <25% lumpy or hard stools	- Increased response rate with 1 L/day Hépar vs. placebo: +16.4% at week 2 (p = 0.013) +14.7% at week 4 (p = 0.028)
Naumann et al. 2016 [34]	RCT, 100 participants (85% female), Rome III criteria with 2–4 bowel movements/week and ≥ 1 L/day water	Ensinger Schiller Quelle 4 × 0.25 L/day	Tap water (108 mg/L) + 2650 mg/L CO2	Difference in stool frequency	- Increased weekly number of stools at 3 weeks vs. placebo (4.80 vs. 3.82, p = 0.036)
Bothe et al. 2017 [35]	RCT, 75 participants (84% females), Rome III criteria with 2–4 bowel movements/week and ≥ 0.3 L/day water	Donat MG 0.5 L/day	Low mineral natural water (<1000 mg/L) + 3500 mg/L CO2	Difference in complete spontaneous bowel movement	- Increased weekly bowel movements vs. placebo: at 3 weeks 6.14 vs. 4.45, p = 0.006 at 6 weeks 6.62 vs. 4.47, p = 0.001.
Dupont et al. 2019 [33]	RCT, 226 participants (100% females), Rome III criteria	Hépar 1 L/day	Low mineral natural water (400 mg/L)	Response to the treatment: ≥4 stools/week or an increase of ≥2 stools per week AND <25% lumpy or hard stools	- Increased response rate vs. placebo at 2 weeks: +21.1% responders (p = 0.001) Response reached in a mean of 6.4 ± 0.6 days (p = 0.013 vs. placebo)

RCT: Randomized, double-blind, placebo-controlled trial.