味苦．入手少阴足太阴经．功专引血化汗．内托痈疽．同丁香治痘疮灰塌．消瘀生肌．补虚寒．宣气血．利关节．治风痹症瘕．噎膈腹满．心腹诸痛．桂枝去皮为桂心．