This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
Properties : Magnesium oxid is a white, very bulky and very fine powder, without odor, and having an earthy but not a saline taste. It is almost insoluble in water and alcohol, but dissolves very readily in acids, forming salts of magnesium.
Action and Uses: Magnesium oxid is used mostly as an antacid to neutralize excessive acidity in the gastric juice. It is especially suitable for cases of hyperacidity accompanied by constipation. It is preferable in most cases to the carbonates or bicarbonates because it yields no gas on being neutralized. It is sometimes given in diarrhea with excessive acidity in children. It is an efficient antidote to the corrosive acids
Dosage: From 0.6 to 3 gm. or from 10 to 45 grains; 2.5 gm. or 40 grains are equivalent to the average laxative dose of magnesium sulphate (15 gm. or 240 grains).