Objective To explore the therapeutic mechanism of QingSeLing (QSLG) on melasma, and to provide scientific basis for clinical application of QSLG. Methods 150 cases with melasma were divided randomly into the test group treated with QSLG and the control group treated with BXD and the control group treated with Vitamine E and Vitamine C. The level of neuropeptide SP and VIP in plasma were measured with radioimmunoassay ( RIA ) before and after the treatment. Results QSLG could decrease the plasma SP content and the plasma VIP content. Its eff...