In Su Tong’s novels, the term madness is more than a medical term and it carries metaphorical meanings. In The Tale of the Siskins and “Madwoman on the Bridge,” Su Tong uses madness as a metaphor to challenge the dichotomy between normality and abnormality, and draws an analogy between mental hospitals and contemporary society. Unlike Yu Hua’s 余華 (1960-) novels, which intertwine sanguinary violence with madness, Su Tong depicts madness mainly to unveil the absurdity of the Mahogany Street. This paper analyses the use of patients’ illnesses in mental hospitals as metaphors in these two stories. In “Madwoman on the Bridge,” Su Tong displaces the role of doctors and madmen. In The Tale of the Siskins, Su Tong dismantles the clear-cut distinction between normality and abnormality. By reversing the two signifying concepts of normality and abnormality, Su Tong leads us to re-assess a variety of conventions, customs and acts we deem reasonable and legitimate in contemporary society.