Method for enhancing in a mammalian cell the activity of an enzyme associated with Gaucher Disease by administering a competitive inhibitor of glucocerebrosidase in an amount effective to enhance the activity of the enzyme. Preferred compounds for use in the method are imino sugars and related compounds. In particular, C8-12-alkyl derivatives of N-alkyl-deoxynojirimycin, isofagomine compounds, and calystegine compounds are effective to enhance glucocerebrosidase activity.