Spring is a period of high incidence of infectious diseases of the respiratory system. Due to the large temperature changes in spring, the immune function and the defense function of the respiratory mucosa of the human body are reduced. Especially in hazy weather, the increase of suspended particles in the air and the higher density of pathogenic microorganisms make it easier for pathogenic microorganisms to invade susceptible people through the respiratory tract. At the same time, the pathogenic microorganisms continue to spread outward with respiratory secretions and invade another susceptible person, which leads to the multiplicity and clustering of respiratory infectious diseases. Respiratory system infections can be broadly divided into upper respiratory tract infections and lower respiratory tract infections. Upper respiratory tract infections mainly refer to the area above the larynx, including the nose, pharynx, and larynx, and are commonly associated with colds, pharyngitis, laryngitis, tonsillitis, and other diseases. Lower respiratory tract infections mainly refer to the area below the larynx, including the trachea, bronchi, bronchial tree, alveoli and other tissues, and common diseases include tracheitis, bronchitis, pneumonia, and tuberculosis. There are various pathogenic microorganisms that cause respiratory tract infections; viruses, bacteria, fungi, mycoplasma, and chlamydia are all common pathogenic microorganisms. Different sites and different pathogenic microbial infections require different drug treatments. While the symptoms of respiratory tract infections lack specificity, fever, cough and sputum may occur in various respiratory tract infectious diseases. When patients develop these symptoms, they should go to the hospital promptly and not blindly buy antibiotics on their own for treatment. Suggestions: To prevent respiratory infectious diseases in spring, pay special attention to prevent cold and keep warm, increase and decrease clothing at the right time, and open windows and ventilate frequently indoors to keep the air fresh. Eat more fresh fruits and vegetables rich in vitamins and drink more warm water. You should also do outdoor activities and exercise to enhance your body’s ability to resist pathogenic microorganisms.