Previous research conducted by our team showed that cooling blood and Yang restraining herbs had a positive clinical effect in the treatment of skin diseases such as blood-heat syndrome, eczema, and psoriasis vulgaris.[12,13] In addition, experiments have shown that the drug for cooling blood and retraining Yang may function by upregulating the expression of PD-1 mRNA, PD-L2 mRNA, and their proteins in patients with psoriasis vulgaris, which is characterized by blood-heat syndrome.[14] The specific composition, dosage, and medicinal parts of herbal components are shown in Table 1. This evidence concerns the gene PDCD1LG2 and psoriasis vulgaris.