Magnesium hydroxide

Magnesium hydroxide is a chemical compound made of magnesium and hydroxide ions. It has the chemical formula Mg(OH)₂. When mixed with water, it becomes a mixture called milk of magnesia.

Uses

Magnesium hydroxide can be made by mixing solutions that have magnesium cations and hydroxide anions. Seawater and quicklime are convenient reactants for making magnesium hydroxide.

Magnesium hydroxide can also be made by mixing water with magnesium oxide.

As a drug

Magnesium hydroxide is used to treat occasional constipation in children and adults on a short-term basis. Magnesium hydroxide is in a class of medications called saline laxatives. It works by causing water to be retained with the stool.