After the formation of an anal fistula, it does not always lead to acute episodes over a long period. Acute episodes of an anal fistula, causing infectious symptoms, occur only when there is a severe localized damp-heat condition. Therefore, the symptoms of an anal fistula are intermittent. The absence of symptoms does not mean that the anal fistula is completely cured or will not recur. Therefore, if an anal fistula is diagnosed, it is necessary to undergo surgical treatment as soon as possible to avoid repeated episodes due to lack of active treatment. Long-term repeated episodes of an anal fistula can lead to thickening of the fistula wall and an increase in branching. Even if an anal fistula is not actively treated over many years, it may even induce carcinogenesis in the local fistula wall.