The present invention relates to the use of the 4 - methyl - 2 - oxo - 2h - 1 - benzopyran - 7 - y 1 - 5 -) - and β - d - xylopyranoside in the treatment of mucopolysaccharidosis such as the disease to maroteaux - lamy.La présente invention concerne lutilisation du 4-méthyl-2-oxo-2H-1-benzopyran-7-yl -5-thio-β-D-xylopyranoside dans le traitement dune mucopolysaccharidose telle que la maladie de Maroteaux-Lamy.