Magnesium hydroxide

Antacid and laxative
ALSO SOLD WITHOUT PRESCRIPTION

Magnesium hydroxide is a antacid and laxative found in 5 medicines sold in India, such as Cremaffin, Gelusil MPS, Cremaffin Plus. Below: what it is for, how it works, how to take it, side effects, interactions and pregnancy advice.

Also called: milk of magnesia

What it is used for

Neutralises acid; in larger amounts it softens stools.

How it works

An antacid that neutralises acid; in larger doses it draws water into the bowel and works as a laxative (milk of magnesia).

How to take it

As an antacid, after meals and at bedtime. As a laxative, 30 to 45 ml at bedtime with water. Keep 2 hours apart from other medicines.

Common side effects

  • Diarrhoea
  • Stomach cramps

Get medical help straight away if

Muscle weakness, slow heartbeat or drowsiness (too much magnesium, especially with kidney disease)

Be careful

Can cause loose motions; caution with kidney disease.

Other medicines and interactions

Reduces absorption of iron, ciprofloxacin, tetracyclines, levothyroxine and some other medicines; separate doses by at least 2 hours.

Pregnancy and breastfeeding

Short-term use is considered acceptable in pregnancy and breastfeeding.

Combination medicines that contain Magnesium hydroxide (5)

CremaffinCremaffin PlusDigeneGelusil MPSMucaine Gel

Common questions

What is Magnesium hydroxide used for?

Neutralises acid; in larger amounts it softens stools.

How does Magnesium hydroxide work?

An antacid that neutralises acid; in larger doses it draws water into the bowel and works as a laxative (milk of magnesia).

How should I take Magnesium hydroxide?

As an antacid, after meals and at bedtime. As a laxative, 30 to 45 ml at bedtime with water. Keep 2 hours apart from other medicines.

What are the side effects of Magnesium hydroxide?

Common: Diarrhoea, stomach cramps. Get help straight away for: Muscle weakness, slow heartbeat or drowsiness (too much magnesium, especially with kidney disease).

Does Magnesium hydroxide interact with other medicines?

Reduces absorption of iron, ciprofloxacin, tetracyclines, levothyroxine and some other medicines; separate doses by at least 2 hours.

Is Magnesium hydroxide safe in pregnancy and breastfeeding?

Short-term use is considered acceptable in pregnancy and breastfeeding.

Does Magnesium hydroxide need a prescription in India?

It is usually sold without a prescription in India, but ask a pharmacist if you take other medicines or have a long-term illness.

Which brands contain Magnesium hydroxide?

Cremaffin, Cremaffin Plus, Digene, Gelusil MPS, Mucaine Gel.

Sources and further reading

NHS (UK National Health Service) and MedlinePlus (US National Library of Medicine) are free, reviewed medicine guides. Brand names and doses there may differ from India.

Last reviewed 31 October 2026. Written by Satya Babu from standard prescribing information.

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For information only, not medical advice. This page is a plain-language summary written from standard prescribing information and the public guides linked below. Brands sometimes change their formula, so always check the composition printed on the pack. Doses here are typical adult doses; yours may differ. Do not start, stop or change a medicine without your doctor or pharmacist, and keep all medicines away from children. In an emergency, call 112 (India) or your local emergency number.