The chemical compound ononitol is a derivative of inositol, specifically 4-O-methyl-myo-inositol: an ether that can be described as the result of replacing the hydroxyl (–OH) in position 4 of myo-inositol by a methoxy group.
This compound occurs in several organisms. It is one of the predominant soluble carbohydrate derivatives in the root nodules of the pea plant created by the bacterium Rhizobium leguminosarum, and a constituent of Medicago sativa.