Abstract: This paper introduces the clinical experience of Professor FAN Ruiqiang in treating mucocutaneous mycosis from the perspective of damp-heat and insect toxin. Professor FAN holds that the core pathogenesis of mucocutaneous mycosis is internal accumulation of damp-heat and invasion of insect toxin that bind with each other, leading to invasion of the skin and mucosa. In treatment,the disease should be treated mainly from the perspective of damp-heat and insect toxin,focusing on clearing heat and eliminating dampness,killing insects and resolving toxins, supplemented by regulating qi and blood,moistening the skin and restoring morphology. Combined internal and external treatment can achieve satisfactory effects.