Disclosed is a pharmaceutical composition comprising a combination of (A) (1S)-1,5-anhydro-1-[5-(4-ethoxybenzyl)-2-methoxy-4-methylphenyl]-1-thio-D-glucitol (Luseogliflozin / TS-071) or a pharmaceutically acceptable salt thereof or a hydrate of the compound or the salt and (B) an insulin sensitizer, selected from rosiglitazone or pioglitazone. Also disclosed is the use of a combination of: (A) Luseogliflozin or a pharmaceutically acceptable salt thereof or a hydrate of the compound or the salt and (B) an insulin sensitizer, selected from rosiglitazone or pioglitazone in the manufacture of a medicament for preventing or treating diabetes mellitus, diseases associated with diabetes mellitus, or complications of diabetes mellitus (such as diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, cerebrovascular disorder, ischemic cardiac disease, or peripheral arterial disease), wherein (A) and (B) are formulated for simultaneous or separate administration.
