仲景治表虛．制桂枝湯．桂枝味辛熱發(fā)散．助陽(yáng)體輕．本乎天者親上．故桂枝為君．芍藥、甘草佐之．陽(yáng)脈澀．陰脈弦．法當(dāng)腹中急痛．仲景制小建中湯．芍藥味酸寒．主收補(bǔ)中．本乎地者親下．故芍藥為君．官桂、甘草佐之．一則治表虛．一則治里虛．各言其主用也．后之人用古方者．觸類而長(zhǎng)之．則知其本而不至于差誤矣．