Coughing after lying down may be related to respiratory diseases, circulatory diseases, digestive diseases and other causes. 1. Respiratory diseases: such as pillow dust mites and other bed allergenic substances can cause bronchial asthma, which can be manifested in coughing after lying down. 2. Circulatory system diseases: such as heart failure and other cardiac insufficiency diseases, venous return increases after lying down, which can cause lung bruising, then the symptoms of coughing. 3. Digestive tract diseases: such as reflux esophagitis, due to lying down can lead to reflux of gastric contents, when it stimulates the throat, can cause coughing symptoms. It is recommended that people who cough after lying down go to the hospital in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.