barley water

a decoction of barley, used especially in the treatment of diarrhea in infants.

Origin of barley water

First recorded in 1275–1325

The two doctors were for keeping him on gruel, lemonade, barley-water, and so on.

The Moonstone |Wilkie Collins
Follow up with demulcent drinks, such as barley-water, flour and water, &c.

Poisons: Their Effects and Detection |Alexander Wynter Blyth
Barley-water and milk, two-and-a-half ounces every two hours—that's five tablespoonfuls, you know.

Lotus Buds |Amy Carmichael
The women moistened its lips with barley-water, and hushed its fretful whimper.

The Manxman |Hall Caine

Then she understood—it was a teetotal drink men took in clubs, a kind of barley-water.

Bud |Neil Munro

barley water

a drink made from an infusion of barley, usually flavoured with lemon or orange