Magnesium Hydroxide – What It Is and Why You Might Need It
If you’ve ever taken Milk of Magnesia for a upset stomach or constipation, you’ve already used magnesium hydroxide. It’s a simple mineral compound that works as both an antacid and a laxative. The dual action makes it a go‑to option for many people who need quick relief without prescription drugs.
How Magnesium Hydroxide Works
When you swallow magnesium hydroxide, it meets the acid in your stomach and turns into magnesium chloride and water. This neutralizes excess stomach acid, easing heartburn and indigestion. In the intestines, the same compound pulls water into the bowels, softening stool and encouraging a natural bowel movement. The result is fast relief for two common complaints: sour stomach and occasional constipation.
When to Take It Safely
The usual adult dose for heartburn is 1–2 teaspoons of liquid or 400‑800 mg of chewable tablets, taken after meals. For constipation, the dose often doubles but you should not exceed the label’s maximum without a doctor’s advice. Kids need smaller amounts, and many brands have pediatric formulas.
Don’t use magnesium hydroxide if you have kidney disease or a blocked intestine. Those conditions can cause the mineral to build up in your body, leading to serious side effects. If you’re on other medications, especially antibiotics or heart drugs, check with a pharmacist first – magnesium can change how some medicines are absorbed.
Side effects are usually mild: a chalky taste, loose stools, or a temporary feeling of fullness. If diarrhea lasts more than two days, cut back the dose or switch to a gentler product. Rarely, people develop an allergic reaction with rash or swelling; seek medical help right away.
Magnesium hydroxide can also be handy outside the bathroom. Some gardeners use it to raise soil pH, and a few home‑brew enthusiasts add it to balance water hardness. While these uses aren’t related to health, they show how versatile the compound is.
If you’re looking for a natural way to soothe heartburn after a heavy meal, magnesium hydroxide is often cheaper than prescription antacids. It’s also widely available at pharmacies, grocery stores, and online retailers. Compare prices and read the label – some products combine magnesium hydroxide with aluminum hydroxide for extra buffering power.
Remember that regular reliance on any antacid can mask underlying digestive issues. If you find yourself reaching for magnesium hydroxide more than twice a week, talk to a doctor about possible causes like GERD or dietary triggers.
In short, magnesium hydroxide is an effective, over‑the‑counter solution for occasional heartburn and constipation. Use the right dose, watch for side effects, and you’ll have fast, reliable relief without needing a prescription.
Magnesium Hydroxide: Chemical Properties, Solubility, Ksp, and Reactions

Clear, practical look at magnesium hydroxide chemistry: structure, Ksp, solubility, pH, reactions, and real-world uses with data, formulas, and pro tips.
28.08.25
Alistair Mukondiwa
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