Magnesium for Constipation Relief

Research suggests that magnesium-based compounds — including magnesium oxide, magnesium citrate, and magnesium-containing mineral waters — show promise as laxative agents, with the most direct support coming from a multi-institutional study of cancer patients showing that prophylactic magnesium oxide significantly reduced opioid-induced constipation rates, and a 2026 review identifying magnesium- and sulfate-rich mineral waters among the dietary interventions with the strongest clinical backing for improving stool frequency and consistency. Studies indicate that magnesium appears across a range of clinical contexts relevant to constipation, including as a component in antacid formulations, enema preparations, and naturopathic protocols, though in most of these cases it is used in combination with other agents, making it difficult to isolate magnesium's specific contribution. The body of evidence is drawn from a heterogeneous mix of study types — including systematic reviews, a multi-institutional analysis, case reports, and expert consensus panels — with no dedicated randomized controlled trials examining magnesium alone as a primary constipation treatment, which represents a meaningful gap. A notable safety concern also emerges from the literature: a case report documented fatal magnesium toxicity in a patient with a bowel obstruction taking routine doses of magnesium-containing antacids, underscoring that while magnesium is generally considered safe for people with healthy kidneys and intact gastrointestinal function, certain medical conditions may alter that risk profile considerably.