朱震亨正式拜师学医时，已经四十四岁——在当时，这是一个很不寻常的年纪。他师从罗知悌（罗氏本人是刘完素的二传弟子），罗知悌当时已年近九十，一年半后便去世，朱震亨几乎是在老师生命的最后阶段才得其真传。他后来创立丹溪学派，主张"滋阴"之说，被列为金元四大家之一。他的三位弟子戴思恭、王履、赵良仁都各有建树。需要说明的是，后世流传甚广的《丹溪心法》，其实是弟子根据他的口述医案整理而成，并非他本人亲笔所著。

Zhu Zhenheng was already forty-four — an unusually late age at the time — when he formally became a disciple of physician Luo Zhiti, himself a second-generation student of Liu Wansu. Luo was nearly ninety by then and died a year and a half later, meaning Zhu received his teaching in the final stretch of his master's life. Zhu went on to found the Danxi school, advocating the theory of "nourishing yin," and is counted among the Four Great Masters of the Jin-Yuan era. His three students — Dai Sigong, Wang Lü, and Zhao Liangren — each went on to their own achievements. It is worth noting that the widely circulated text Danxi's Experiential Therapy was in fact compiled by his students from his orally recorded case notes, not written by Zhu himself.