The problem of the present invention is to provide a highly effective therapeutic drug for pancreatic cancer and/or biliary tract cancer.A therapeutic drug for pancreatic cancer and/or biliary tract cancer containing the following (1) and (2) as essential components:(1) at least one kind of branched-chain amino acid selected from the group consisting of isoleucine, leucine and valine,(2) gemcitabine or a salt thereof.
