GM-XANTHO

This trial is a Phase IIa clinical trial. Around 65 subjects will be enrolled into this study to primarily assess the treatment efficacy of 5% GM-XANTHO in patients with psoriasis, as well as the safety and tolerability of 5% GM-XANTHO. Two third of the total subjects will be given the investigational product, 5% GM-XANTHO, and the other third will take placebo. The treatment period will last for 28 consecutive days, followed by a safety follow-up for 2 weeks. During the study, there will be 8 scheduled visits to the clinical center.