To evaluate the efficacy and safety of a Chinese medicine (CM) Modified Qufeng Runmian Powder (, MQFRMP) for the treatment of acne vulgaris with CM syndromes of dampness and blood stasis.In this multicenter, randomized, double-blind, placebo-controlled clinical trial, 220 acne vulgaris patients with CM syndrome of dampness and blood stasis were included and randomly assigned using a central area group random design to receive either MQFRMP or the placebo, with 110 cases in each group. MQFRMP or a placebo at 145 g/bag were administered once daily for 4 weeks, respectively. The primary index of efficacy was the effective rate according to the acne severity score (ASS). The secondary indices of efficacy included the changes in the dermatology life quality index (DLQI) score, VISIA scores (spots, pores, brown spots, porphyrins and red areas) and skin assessment (skin pH, sebum amount and hydration) according to a SOFT skin multianalyzer.(1) Follow-up: a total of 204 patients completed the follow-up, with 103 in the treatment group and 101 in the control group. (2) Effective rate: the total effective rate of the treatment group was significantly higher than the control group [83.5% (86/103) vs. 31.7% (32/101), P<0.01)] with 95% confidence interval of 39.3%-66.4%. (3) DLQI: DLQI scores were significantly decreased the treatment and control groups (both P<0.01), but the treatment group was more obvious than the placebo group (P<0.01). (4) VISIA scores: the scores of spots, brown spots and red areas in the treatment group decreased compared with baseline (P<0.05). In the control group, the scores of brown spots and pores decreased compared with baseline (P<0.05). The improvement was more obvious in the treatment group than in the control group for all items (P<0.05). (5) Skin assessment: the pH and sebum score in the both groups decreased drastically compared with the baseline (all P<0.01), however, the improvement was more obvious in the treatment group than in the control group (P<0.01). The hydration amount in the two groups showed no statistically significant difference compared with the baseline (both P>0.05). (6) Safety: two cases of mild drug allergy were observed in the treatment group.MQFRMP was effective and safe for the treatment of acne vulgaris with syndromes of dampness and blood stasis. (No. ChiCTR1900020479).