味苦咸性降．入手足太陰陽明經(jīng)．功專逐腑積聚．得大黃直入大腸．滌垢通經(jīng)墮胎．芒硝經(jīng)煉稍緩．能柔五金化七十二石為水．生于鹵地刮取煎煉在底者為樸硝．在上者為芒硝．有牙者為馬牙硝．置風(fēng)日中消盡水氣．輕白如粉為風(fēng)化硝．大黃為使．