Abstract: Esters associating phenylacetic, 3-phenylpropionic, 4-phenylbutyric and n-butyric acids with Su(OH).sub.n monosaccharides or sugar alcohols, of general formula (I), in which the Su(OH).sub.n precursor is a monosaccharide or sugar alcohol, selected so that its structure or that of its derivatives ensures that internal interesterification does not take place either because the ester based on the general formula does not have a free hydroxyl grouping, or because with regard to the ester grouping, the free hydroxyl groupings are remotely located and/or badly aligned and/or bonded to a secondary carbon atom, and in which the Su(OH).sub.n monosaccharide or sugar alcohol is preferably D-mannose carrying the ester grouping on the anomeric carbon atom or else is a pentitol, for example, xylitol carrying the ester grouping on the C-1 primary carbon atom. These novel esters are useful as drugs, in particular in the treatment of haemoglobin diseases and premalignant or malignant tumours.