Hordeum Vulgare—common Barley—is chiefly used in Great Britain for brewing and distilling; but, it has dietetic and medicinal virtues which entitle it to be considered among serviceable simples. Roman gladiators who depended for their strength and prowess chiefly on Barley, were called Hordearii. Nevertheless, this cereal is less nourishing than wheat, and when prepared as food is apt to purge; therefore it is not made into bread, except when wheat is scarce and dear, though in Scotland poor people eat Barley bread. In India Barley meal is made into balls of dough for the oxen and camels. Pearl Barley is prepared in Holland and Germany by first shelling the grain, and then grinding it into round white granules. The ancients fed their horses upon Barley, and we fatten swine on this grain made into meal. Among the Greeks beer was known as barley wine, which was brewed without hops, these dating only from the fourteenth century.
A decoction of barley with gum arabic, one ounce of the gum dissolved in a pint of the hot decoction, is a very useful drink to soothe irritation of the bladder,  and of the urinary passages. The chemical constituents of Barley are starch, gluten, albumen, oil, and hordeic acid. From the earliest times it has been employed to prepare drinks for the sick, especially in feverish disorders, and for sore lining membranes of the chest. Honey may be added beneficially to the decoction of barley for bronchial coughs. The French make "Orgeat" of barley boiled in successive waters, and sweetened at length as a cooling drink: though this name is now applied in France to a liqueur concocted from almonds.
From the Heritage Herbs Collection by M.G. Kains, American Agriculturist, 1912.