To investigate the expression and significance of substance P(SP) and its neurokinin-1 receptor(NK-1R) in psoriatic skin tissue after intervention with Rumex obtusifolius L.Methods:Skin and blood samples were collected from control mice，psoriasis model mice，and mice treated with methotrexate tablets(1.3 mg/kg)，aprepitant capsules(5 mg/kg)，and R.obtusifolius at doses of 1，2，and 4 g/kg.Hematoxylin and eosin(HE) staining was used to observe the pathological changes in psoriatic skin tissues.Real-time fluorescence quantitative polymerase chain reaction(RT-qPCR) was employed to detect the expression of SP and NK-1R mRNA in psoriatic skin.Enzyme-linked immunosorbent assay(ELISA) and Western blot were used to measure the expression of SP in serum and NK-1R protein in the skin.Subsequently，the relationship between the expression levels of SP，NK-1R，and psoriasis was analyzed.Results:Compared to the psoriasis model group，all drug intervention groups showed improvements in the pathological changes of psoriatic skin tissue and reduced expression of SP and NK-1R mRNA in the skin，and SP in serum，as well as NK-1R protein in the skin(P<0.05，P<0.01).Compared to the positive control drugs methotrexate and aprepitant，the R.obtusifolius group at 1 g/kg showed increased expression of NK-1R protein in the skin tissue(P<0.05).Compared to the results in the R.obtusifolius group at 1 g/kg，the expression of NK-1R protein in the skin tissue was decreased in the R.obtusifolius groups at 2 g/kg and 4 g/kg，with the 2 g/kg group showing a non-significant decrease(P>0.05) and the 4 g/kg group showing a significant decrease(P<0.05).Conclusion:R.obtusifolius may improve psoriasis-like skin lesions in mice by reducing the expression of the anxiety-related neurotransmitter SP and its receptor NK-1R at both the gene and protein levels.Its effectiveness is comparable to the positive control drugs methotrexate and aprepitant.