Dextrose Monohydrate (C6H12O6), also known as D-glucose, dextrose, or grape sugar) is a simple sugar (monosaccharide) and an important carbohydrate in biology. Cells use it as a source of energy and a metabolic intermediate. Dextrose Monohydrate is one of the main products of photosynthesis and starts cellular respiration.

Dextrose Monohydrate exists in several different structures, but all of these structures can be divided into two families of mirror-images (stereoisomers). Only one set of these isomers exists in nature, those derived from the "right-handed form" of Dextrose, denoted Dextrose Monohydrate. Dextrose Monohydrate is often referred to as D-glucose. The term dextrose is derived from dextrorotatory glucose. Solutions of dextrose rotate polarized light to the right. Starch and cellulose are polymers derived from the dehydration of Dextrose Monohydrate. The other stereoisomer, called L-glucose, is hardly found in nature.

In industry, Dextrose Monohydrate is used as a precursor to make vitamin C in the Reichstein process, to make citric acid, gluconic acid, bio-ethanol, polylactic acid, sorbitol.