[1] Thereafter he switched his sights to medicine; a topic his father had introduced him to together with Chinese philosophy,[3] spending more than a decade studying it[1] on his own.

[6] In 1926, he established the Tianjin Institute for Integrated Chinese and Western Medicine, which attracted "hundreds of students from across the country".

[1] About two years afterwards, he formulated a treatment for febrile arthritis combining aspirin with a traditional Chinese medicine, gypsum fibrosum.

[3]He also believed that modern and traditional medicine shared a common set of principles and thought that Western medical knowledge could be proof for ancient Chinese beliefs, such as in the case of determining that the heart cannot function without the brain.

[9] Zhang is considered as one of the "four masters of medicine" of China, the other three being Liu Weichu, Yang Ruhou, and Lu Jinsheng.