"Multiple use of single formula" is reflected in the flexible use of classical and current formulas by modifying the compositions based on pattern differentiation. The use of classical and current formulas in the clinical practice should be in line with the main pathogenesis

and can be flexibly modified according to the secondary pathogenesis

different pathogens

and differences in location

thereby evolving into varied treatment methods which can be used for varied diseases. This paper summarized professor MEI Guoqiang′s thought on "multiple use of single formula"

who advocates to follow the original of the classics and put focus on their expansion

to distinguish the main and secondary pathogenesis and combine with other prescriptions

and to distinguish pathogens

concurrent and complicated symptoms

and modify the compositions flexibly. The multiple use of three formulas

namely Xiaoxianxiong Decoction（小陷胸汤）

Ermiao Decoction（二妙汤）

and Jiaoai Decoction（胶艾汤）

was taken as examples. Method of rectifying qi

invigorating blood

and diffusing the lung by Xianxiong Decoction

relieving pain method

relieving itching method and resolving toxins method by Ermiao Decoction

as well as nourishing blood method

boosting qi method and enriching yin method by Jiaoai Decoction have been used to expand the clinical application of classical formulas in a flexible way.