Cough may be caused by inhalants, infections, diseases, etc. There are many reasons for a normal cough blood test, which is commonly seen in cough variant asthma and gastroesophageal reflux disease. 1. Cough variant asthma: it may be caused by climate change, inhalation of cold air, respiratory tract infections, allergens and other factors, and there will be symptoms of irritating cough, normal blood test, you can use budesonide, salbutamol and other drugs under the guidance of the doctor for treatment. 2. Gastroesophageal reflux disease (GERD): it is a disease caused by reflux of gastric contents, which may cause severe pain behind the sternum, irritation of organs other than the esophagus by gastric reflux, irritation of the larynx causing a foreign body sensation in the pharynx, and coughing, etc. It can be treated with medicines such as Ranitidine and Omeprazole under the guidance of a doctor. There are many reasons for the normal cough blood test, it is recommended to go to the hospital in time to clarify the cause of the disease, under the guidance of the doctor for treatment.