To summarize Professor AI Rudi's experience in the staged external treatment of eczema by traditional Chinese medicine （TCM）. It is believed that dampness is the key pathological factor of eczema， and the treatment for dampness should be carried out throughout the whole process， with the leading idea of “three-stage treatment， dampness as the root， and treatment according to the symptoms”. The preparation and formulas of the external treatment can be applied according to the pathogenesis and lesion characteristics of each stage. In acute stage with wind-dampness and heat in the skin as the main mechanism， the treatment is to clear heat and astringe， resolve toxins and relieve itching， and the preparation is mostly solution and lotion， and the formula could be Yangzheng Xi Formula （痒症洗方）， Jingfang Kushen Decoction （荆防苦参汤）， Kuding Erhuang Decoction （苦丁二黄汤）， and Xianglian Jinhuang Powder （香连金黄散）. In subacute stage with phlegm-dampness and heat as the main mechanism， the treatment is to remove dampness and turbidity， clean up the residual heat； the preparation is mostly ointment， and the formula include Shehuang Ointment （蛇黄软膏）， Huanglian Ointment （黄连膏）， and Zihuan Diding Ointment （紫花地丁软膏）. In chronic stage with phlegm-dampness stagnation as the main mechanism， the treatment is to remove dampness and eliminate phlegm， remove blood stasis and stop itching， and the formula could be Zhiyang soft Ointment （止痒软膏）， Runji Ointment （润肌膏）， Yufu Ointment （愈肤膏）； jojoba oil and olive oil are often used as external moisturiser for daily care.

Objective To investigate the effect of Yipi Yanggan prescription on the malignant transformation of liver stem cells in liver precancerous lesion induced by diethylnitrosamine (DEN) and its possible molecular mechanism. Methods A total of 35 male Sprague-Dawley rats were randomly divided into normal control group (blank group), DEN model group (model group), DEN+Yipi Yanggan prescription group (Yipi Yanggan prescription group), and DEN+Hugan tablet group (Hugan tablet group), with 5 rats in the blank group and 10 rats in the other three groups. Intraperitoneal injection of DEN was performed to establish a model of liver precancerous lesion, the rats were sacrificed after 16 weeks of administration. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and albumin (Alb) were measured; liver tissue was collected to observe the changes in size and appearance and calculate liver weight ratio (liver index); HE staining and Sirius Red staining were used to observe the pathological and morphological changes of rat liver tissue; immunohistochemistry was used to measure the expression of OV6 and glutathione S-transferase-Pi (GST-Pi); RT-PCR was used to measure the mRNA expression of EpCAM, CD133, and CD90, and Western blot was used to measure the protein expression of PI3K, Akt, and mTOR and their phosphorylation level. A one-way analysis of variance was used for comparison between multiple groups, and the least significant difference t -test was used for further comparison between two groups. Results Compared with the model group, the Yipi Yanggan prescription group and the Hugan tablet group had significant improvements in liver pathology and morphology, significant reductions in liver index and the levels of ALT and AST, and a significant increase in the level of Alb (all P < 0.05), as well as significant reductions in the protein expression levels of GST-Pi, OV6, p-PI3K, p-Akt, and p-mTOR and the mRNA expression levels of EpCAM, CD133, and CD90 (all P < 0.05). Compared with the Hugan tablet group, the Yipi Yanggan prescription group showed a more significant protective effect on the liver, with significant reductions in liver index and the levels of ALT and AST, and a significant increase in the level of Alb (all P < 0.05), as well as significant reductions in the protein expression levels of GST-Pi, OV6, p-PI3K, p-Akt, and p-mTOR and the mRNA expression levels of EpCAM, CD133, and CD90 (all P < 0.05). Conclusion Yipi Yanggan prescription can improve liver precancerous lesion induced by DEN in rats by inhibiting the malignant transformation of liver stem cells, and its mechanism of action may be associated with the PI3K/Akt/mTOR signaling pathway.