Fungal diseases, are infectious diseases caused by fungi. Fungi are a class of eukaryotic cellular organisms that exist widely in nature and absorb nutrients in a parasitic and saprophytic manner. The most suitable growth conditions for fungi are temperature 22℃～36℃, humidity 95%～100%, pH5～6.5. Fungi are not heat-resistant, most of them die in a short time at 100℃, but they can survive for a long time at low temperature; UV and X-ray can not kill fungi, formaldehyde, carbolic acid, tincture of iodine and peroxyacetic acid and other chemical disinfectants can kill fungi quickly. Human infection with fungi mainly from the external environment, and through contact, inhalation or ingestion and infection. A few pathogenic fungi can cause disease directly, and most fungi cause disease under certain conditions, the latter being called conditionally pathogenic fungi. Dermatophytosis is contagious by contact, and unclean hygiene practices, sweaty impregnation, sharing slippers, towels, combs and contact with ringworm-afflicted animals are the main routes of transmission of dermatophytes.