When you have a dry cough and no phlegm from a cold, it is likely that the cold has caused laryngitis. It is necessary to go to the ENT department and have the doctor check the throat for congestion and edema. If the dry cough and lack of phlegm are caused by pharyngitis, antiviral medication is needed to treat the inflammation. For example, you can take oral anti-inflammatory medicine such as Pudilan, Ribavirin, or Scutellaria orally for anti-inflammatory treatment. For a dry cough without phlegm, you need to use cough medicines to relieve the discomfort caused by this symptom, for example, you can take oral fenagan syrup. If there is no obvious congestion and edema in the throat, it is likely that the dry cough and absence of sputum is caused by inflammation of the airways. At this time, blood tests are needed. If there are elevated white blood cells in the blood, antibiotics should be given for anti-inflammatory treatment. At this time, cough and expectorant medications are needed to relieve the symptoms of dry cough and no sputum, such as pulmonary cough combination or tranylcypromine oral solution.