In this study, we found substantial increase in splenic mRNA expression of Notch1 and its target gene Hes-1 in IMQ-induced mouse psoriasis-like skin inflammation, which closely resembles human psoriasis, presenting as erythema, scaling and thickening in phenotypical characters as well as obviously epidermal hyperplasia, massive inflammatory cells infiltration and capillary dilation in pathological changes. The gene discussed is NOTCH1; the disease is Erythema.