Abstract：This study analyzes Xiao Er Dou Zhen Fang Lun （Discourse on Treatment for Children with Exanthema Variolosum） written by CHEN Wenzhong， a physician of the Southern Song Dynasty， and summarizes his academic thoughts on the diagnosis and treatment of exanthema variolosum. The analysis suggests that CHEN Wenzhong proposed the "three filthy liquid toxins" as the source of exanthema variolosum. He emphasized differentiating the severity， exterior-interior， deficiency-excess， and true-false cold-heat patterns in the diagnosis of exanthema variolosum. He advocated the treatment concept of "prioritizing yang consolidation and cautiously using cold-cooling methods" and the treatment principles of "supporting the interior，promoting free flow，and nourishing the defensive and nutritive qi."