This article reviews the effi cacy and safety of an old drug tranexamic acid about its new use in the treat-ment of melasma. Its mechanism of preventing the activation of melanocyte from UV light, hormone and injured kerationcyte through the inhibition of the plasminogen activator system will be explored and compared with current treatment for melasma. More and more clinical studies have shown that oral and(or) local administration of tranexamic acid alone or combined with other methods is effective and saf...