The present invention relates to a bioactive agent capable of increasing the intracellular concentration and/or activity of Hsp70 for use in the treatment of a lysosomal storage disease which arise from a defect in an enzyme whose activity is not directly associated with the presence of lysosomal BMP as a co-factor； such as glycogen storage diseases, gangliosidoses, neuronal ceroid lipofuscinoses, cerebrotendinous cholesterosis, Wolman's disease, cholesteryl ester storage disease, disorders of glycosaminoglycan metabolism, mucopolysaccharidoses, disorders of glycoprotein metabolism, mucolipidoses, aspartylglucosaminuria, fucosidosis, mannosidoses, and sialidosis type II.
