The invention is directed to a microorganism-killing combination comprising a photosensitizer in an amount effective to kill microorganisms in a photodynamic process and a chitosan in an amount effective to enhance the microorganism-killing effect of the photosensitizer in the photodynamic process. The invention also provides the methods of administering the synergistic bacteria-killing combination to kill bacteria or treat infection.本發明係關於一種殺微生物組合,其包含一種於光動力過程殺微生物有效量之光感物質,以及一種於光動力過程增進該光感物質之殺微生物作用有效量之幾丁聚糖(chitosan)。本發明亦提供施用具協同作用之組合以殺細菌或治療感染之方法。(無元件符號說明)