Abstract: There disclosed a boiler compound which comprises as the effective components thereof: (A) metabisulfurous acid or metabisulfites; (B) aliphatic dicarboxylic acids or salts thereof represented by the general formula:M.sup.1 OOC--(CH.sub.2).sub.n --COOM.sup.,wherein M.sup.1 and M.sup.2 are each a hydrogen atom, a sodium atom, a potassium atom or an ammonium group and n is an integer of 1 to 10; and optionally (C) a water-soluble polymer for scale inhibitor. The boiler compound is safe for human health, has excellent stability, can be used as a liquid formulation having anticorrosion activity (activity of eliminating oxygen) or both of anticorrosion activity and antiscale activity and exhibits enhanced anticorrosion activity by increasing concentration of sulfite ion which is an oxygen scavenger.

Abstract: A corrosion inhibitor which comprises tannic acid and/or salt thereof; a sugar; and at least one member selected from aldonic acids or hexoses or salts thereof and aldonic acids of heptoses of salts thereof.