Dose.—The ordinary dose of this agent as a cathartic is ℥j. It may be conveniently administered in soda water, with lemon syrup. It is sometimes employed in combination with sulphuric acid, as—Rx Aqueous solution of sulphate of magnesia ℥viij., dilute sulphuric acid ʒj.; a tablespoonful in a wineglass of water.
Therapeutic Action.—Sulphate of Magnesia is cathartic, refrigerant and diuretic, possessing the characteristics of most of the saline cathartics. It is considered a mild, safe, refrigerant and hydragogue cathartic. Although nauseous and unpleasant to the taste, it is more acceptable to the stomach than many less unpleasant articles. It acts upon the whole extent of the intestinal canal, producing numerous and copious watery evacuations. Often combined with other cathartics to modify their effects.