Described herein is a corrosion inhibitor for use in an aqueous brine solution; the brine solution may be a drilling fluid or refrigeration fluid. The corrosion inhibitor comprises a reducing sugar, such as a monosaccharide, a disaccharide, a polysaccharide, or any combination thereof. A method of drilling a borehole is also described; the method comprises injecting a drilling fluid into the borehole, wherein the drilling fluid comprises an aqueous brine solution comprising a reducing sugar as a corrosion inhibitor.