A method for treating a flavivirus infection includes administering to a subject in need thereof a composition which includes at least one of gentamicin sulfate, netilmicin, tobramycin, paromomycin, amikacin, capreomycin, trifluoperazine, dihydrostreptomycin, hydroxychloroquine, thioridazine HCl, efavirenz, miltefosine, nystatin, micafungin, bleomycin, resminostat, montelukast, norfloxacin, nedaplatin and cephalothin, which can exhibit excellent growth inhibition or killing effects of various species of flavivirus genus.