The identification of the evidence should be based on the tongue and pulse, not on the length of the illness alone, and not on the use of cold, which will injure Yang Qi and make it difficult to heal for a long time; nor on the use of dryness, which will deplete fluids and make the phlegm sticky and difficult to cough. For external coughs, it is advisable to fight quickly, and for internal coughs, it is prudent to use wind-drying drugs. A prolonged cough can be treated by first draining the liver so that the qi flow can be relaxed and ready for the drugs to take effect. Cultivating the earth to produce gold often yields good results, while astringing the lung to stop coughing is hardly successful. Those with heat should be moistened, while those with cold should be warmed.