张从正私淑刘完素之学，主张「邪去正安」，认为治病应以祛邪为先，擅用汗、吐、下三法攻逐病邪，反对滥用温补，形成「攻邪派」，是金元四大家之一。他将自己与弟子的临证问答、医案整理成《儒门事亲》，「儒门事亲」取意熟谙医理如同儒者奉行孝道侍奉双亲，书中大量记录了他与弟子麻知几、常仲明等人的诊疗对话，是研究其学术思想的核心文献。

Zhang Congzheng studied Liu Wansu's theories independently (without direct discipleship) and held that "once the pathogen is expelled, the body's own vitality is restored," advocating that treatment should prioritize expelling pathogenic factors through sweating, vomiting, and purging rather than tonification — founding the "Attacking Pathogens School" and earning his place among the Four Great Masters. He compiled his clinical dialogues and case records with his students into Confucians' Duties to Their Parents, whose title likens mastering medicine to a Confucian scholar's filial duty; the book records extensive exchanges with students such as Ma Zhiji and Chang Zhongming and remains the central text for studying his thought.