Magnesium Hydroxide – What It Is and Why You Might Need It

If you’ve ever taken Milk of Magnesia, you already know magnesium hydroxide. It’s a simple mineral that works as an antacid to calm stomach acid and as a laxative to relieve constipation. Most people grab it when heartburn hits hard or when they’re stuck on the toilet for too long. The good news? It’s cheap, easy to find, and usually safe when you follow basic guidelines.

How to Use Magnesium Hydroxide Safely

First off, read the label – it tells you the exact amount of magnesium per dose. For heartburn, adults typically take 1–2 teaspoons (5‑10 ml) of the liquid form, or a chewable tablet, every few hours as needed. Don’t exceed four doses in 24 hours unless your doctor says otherwise.

If you’re using it as a laxative, the dose is higher – about 1–2 tablespoons (15‑30 ml) for adults, taken once before bedtime. The medicine works overnight, drawing water into the intestines and softening stool so you can go in the morning.

Kids need much less. For children aged 2‑12, the usual dose is ½ teaspoon (2.5 ml) of liquid for constipation or a pediatric‑specific chewable tablet for heartburn. Always double‑check with a pediatrician before giving it to kids.

Potential Side Effects & When to Call a Doctor

Magnesium hydroxide is gentle, but you might feel some cramping, gas, or an urgent need to use the bathroom after a laxative dose. Those symptoms are normal and usually fade quickly.

If you notice persistent diarrhea, severe stomach pain, or signs of dehydration (dry mouth, dizziness), stop using it and call your doctor. Also watch out for high magnesium levels if you have kidney disease – that can be dangerous.

Allergic reactions are rare but possible. If you get a rash, itching, or trouble breathing, seek medical help right away.

In everyday life, magnesium hydroxide is a handy tool for two common problems: acid reflux and constipation. It’s inexpensive, works fast, and has a long track record of safety when used as directed. Keep it in your medicine cabinet, but treat it like any other drug – follow the dosing instructions, store it out of kids’ reach, and talk to your pharmacist if you’re unsure about interactions with other meds.

Got more questions? Think about how often you need it. If you find yourself reaching for magnesium hydroxide multiple times a week, that might signal an underlying issue worth discussing with a healthcare provider. Sometimes diet changes or other treatments can reduce the need for over‑the‑counter relief.