Glyoxylic acid is a 2-oxo monocarboxylic acid that is acetic acid bearing an oxo group at the alpha carbon atom. It has a role as a human metabolite, an Escherichia coli metabolite, a Saccharomyces cerevisiae metabolite and a mouse metabolite. It is a 2-oxo monocarboxylic acid and an aldehydic acid. It is a conjugate acid of a glyoxylate.