Milk of magnesia is an over-the-counter (OTC) treatment for constipation. It works by drawing water into the bowel and softening stool, making passing easier. It can also soothe indigestion and ...

Milk of magnesia is used to treat heartburn and constipation. It is a common over-the-counter (OTC) medication. Milk of magnesia, used as a laxative and antacid, brings rapid relief of symptoms.