"肛門膿瘍是指肛門直腸周圍熱毒蘊積形成膿腫，甚至潰而成漏的症狀。其表現的症狀為實證，但究其本則有虛有實，本文即是報告一位50歲女性因為乳癌接受放療後發生肛門膿瘍的一個本虛標實之案例。患者曾至西醫治療但仍反覆發作，傷口不易癒合而至本院中醫門診就醫。經診斷為中醫外科之肛癰，病因病機為氣陰兩虛，濕熱之毒乘虛聚結於肛周。治療過程中患者之肛門膿瘍曾因長途旅行而復發，並因肛門膿瘍演變成肛門瘻管而接受漏管切除術（Fistulectomy）。整個治療的主軸以托裏消毒散為主方來扶正排膿，並以石膏煎水來清熱生肌，再加養陰清熱法退虛火，經過半年的治療，病情獲得穩定的控制，本文對此治療過程作一介紹及討論。Anal abscess is the pus formation around the anal and rectal region induced by the heattoxin. However, the pus formation could possibly break and lead to drainage. Although anal abscess acts like an excessive symptom (實症 ), it may be resulted either excess or deficiency. This paper is a report of a 50-year-old woman suffering from anal abscess, caused by deficiency, after radiotherapy for breast cancer. The patient had received western medicine therapies, but the wound at the anus did not heal well. She then came to our hospital for traditional Chinese medicine therapy. Her anal abscess was diagnosed as anal carbuncle (肛癰 ), resulted from the accumulation of Qi and Yin deficiency (氣陰兩虛 ) and dampness-heat-toxin (濕熱毒邪 ) in the perianal region. During the course of treatment, patient’s anal abscess recurred due to longdistanced travel. It then led to anal fistula, where she finally accepted Fistulectomy. The treatment was mainly based on The Tao Lei Choa Deo Decoction (托裏消毒散 ) to support qi and remove the abscess. In addition, gypsum (石膏煎水 ), which reduce heat and heal wound, was combined with the formula of nourishing yin and reducing heat. After six months of treatment, the symptom was relieved. This paper is a description of the course of treatment and discussion. "