Solution of potassa is sometimes given as a medicine by physicians. Caustic potassa (vegetable caustic) is the solid stick, which, with care, may be used to destroy warts. More often, bicarbonate of potassium is employed as an antacid, in ten or twenty-grain doses; and as an ingredient in effervescing draught (which see). This bicarbonate is also the sal aeratus (gaseus salt) of the bakery ; as, like bicarbonate of sodium, it gives off carbonic acid gas when an acid, such as tartaric acid, is added to it.