Zhu Zhen-heng, a native of Wuzhou Yiwu (now Yiwu County, Zhejiang Province), was respectfully referred to as "Danxi Weng" because his family had long resided in Danxi.

Zhu was intelligent and studious from a young age, studying the classics with the intention of advancing through the imperial examinations to enter officialdom. Later, he went to Mount Bahua to study the theories of morality and human nature under the Neo-Confucian scholar Xu Qian, gaining deep insights into Neo-Confucianism. He abandoned his pursuit of the imperial examinations and devoted himself entirely to medicine.

In the summer of the Yichou year of the Taiding era (1325), he became a disciple of Luo Zhi-ti, who taught him the doctrines of Liu Wan-su, Li Dong-yuan, and Zhang Zi-he, interpreting their teachings through classical texts. After completing his studies, Zhu returned to his hometown, and within a few years, his reputation as a physician flourished.

Danxi excelled in literature and ancient philosophy, adeptly connecting the philosophical ideas from the Book of Changes and Book of Rites with the Neijing, making significant contributions to medical theory. His theories of "excess yang and insufficient yin" and "ministerial fire" had a profound influence on later generations.

Danxi authored works such as Gezhi Yulun, Taiping Huimin Heji Jufang Development, Bencao Yanyi Buyi, Cold-Damage Disease Differentiation, and New Theories on Waike Jingyao. Additionally, books like Maiyin Zhengzhi, Danxi Xinfa, and Jingui Gouxuan were also attributed to Danxi, though some were compiled by his disciples or falsely attributed.

Danxi proposed the theories of "excess yang and insufficient yin" and "ministerial fire" during an era when Tongfang was prevalent and warm dryness was customary. In health preservation, he advocated for the protection of yin essence, and in treatment, he emphasized nourishing yin and reducing fire, making significant contributions to the enrichment and development of medical theory. Later generations referred to him as the "Yin-Nourishing School" and included him among the Jinyuan Sidajia, marking the high esteem and praise he received. However, his insufficient emphasis on yang qi led to some one-sided shortcomings.