Compendium of Materia Medica
Altogether, the writing of "Compendium of Materia Medica" took 27 years, which included three revisions. Ironically, writing the book allegedly took a toll on his health. It was rumored that he stayed indoors for ten consecutive years during the writing of the "Compendium of Materia Medica". After he had completed it, a friend “reported that Li was emaciated.”