Key Lab of TCM Stagnant Heat Pathogenesis of State Administration of Traditional Chinese Medicine was established in 2009 upon the approval of State Administration of Traditional Chinese Medicine. Research directions: (1) research into the syndrome differentiation theory system of TCM pathogenesis; (2) research into the emergency pathogenesis (stagnant heat) of TCM internal medicine; (3) research into stubborn disease pathogenesis (stagnant heat) of TCM internal medicine.