Professor Feng Xian-zhang is good at using the academic ideas of four examinations and eight principles of TCM, the combination of syndrome differentiation and disease differentiation, and the combination of internal and external treatment to guide clinical treatment.He has always achieved good efficacies in treating a variety of common skin diseases and complicated diseases.Gentian Liver-Draining Decoction has the effect of purging liver and gallbladder excess fire and clearing dampness and heat of lower energizer.It is mainly used to treat the syndrome of up-flaming of liver and gallbladder excess fire or the syndrome of liver and gallbladder dampness pouring down.Professor Feng believes that the pathogenesis of herpes zoster is deficiency, blood stasis, dampness, heat and toxin.The nature of the disease is deficiency as primary and excess as secondary.In the acute stage, Modified Gentian Liver-Draining Decoction is often selected.In the later stage, the medicinals for replenishing qi and strengthening healthy qi are often added.The pathogenesis of eczema is dampness, heat, deficiency and blood stasis.The acute eczema is mainly manifested as dampness heat, while the subacute eczema is mainly manifested as spleen deficiency and dampness accumulation, the chronic eczema is mainly manifested as blood deficiency, wind dryness.If heat is more severe than dampness, Gentian Liver-Draining Decoction, and Modified Five Ingredients Toxin-Removing Beverage can be used.If dampness is more severe than heat, Gentian Liver-Draining Decoction, and Modified Stomach-Calming Poria Decoction for removing dampness can be used.The etiology and pathogenesis of skin pruritus include wind, dampness, heat and dryness.The treatment methods include relieving itching by clearing away heat and eliminating wind, or clearing away heat and eliminating dampness, or nourishing yin and moistening dryness, so Gentian Liver-Draining Decoction plus the medicinals for removing wind and relieving itching can be used.In addition, Professor Feng has applied Gentian Liver-Draining Decoction to contact dermatitis, rosacea, neurodermatitis, erythema nodosum, erythema multiforme, tinea pedis infection, pemphigus vulgaris and other skin diseases with dampness-heat syndrome, and always achieved good clinical efficacies.