過去關於台灣SARS 經驗的批判多半建立在政治衝突與風險管理的理性模式，忽略了現代社會心理的集體危機療癒面向，因而未能透視源於社會自我保衛時可能出現的集體暴力。本研究以邊界危機中的污染與淨化儀式切入，分析SARS 危機中遭到集體隔離的兩個社群：華昌國宅住戶與街友之處遇。透過隔離決策與執行過程的歷史分析與回溯訪談，本研究指出在面對突如其來的災難與危機時，社會透過儀式性懲罰做為重新劃定道德邊界的工具，納入道德污染的群體做為代罪羔羊，並擴大對於跨越邊界社群的淨化儀式，以恢復道德秩序；而疑似污染的不同社群也因為所處的地位差異，發展出回應危機的不同模式。在有關SARS 的傳染與臨床通報相關科學知識日益清楚之際，關於劃定群體邊界的風險評估反而日益模糊，國家藉由舉行污染社群的淨化儀式，重新確定危機中的集體道德秩序，此舉強化了國家對於邊緣社群控制的合法性，卻同時隱藏了民主社會中的集體暴力。

Over the past decade, studies on the crisis of the SARS in Taiwan mainly came from the perspectives of political conflicts and risk governance. On the base of rationalism, both theories may have ignored the sociopsychological dimension that a society may legalize its use of collective violence to recover itself from the crisis. This study adopts Douglas’ concept of pollution to analyze two communities which have been discriminated and ignored: the habitants in Huachang public housing and homeless people in Wanhua district, Taipei City. By evaluating the policy decision and reviewing the implementation of isolation and quarantine on them, this study shows how these two groups were identified and punished by the purifying rituals in response to public anxiety. However, the two groups developed different strategies for dealing with discrimination and stigmatization. At the rising of the crisis, the criteria for evaluating SARS cases was so unclear and blurred that many innocent deviant populations were incorrectly included. Through ritual purification toward these groups, the state scapegoats them to reconfirm the boundary of moral and social order. In so doing, it also disguised the legalization of collective violence and the power of state upon shifting deviants in a democratic society.