Three-month-old babies are prone to upper respiratory tract infections because of their low immune function. Upper respiratory tract infections are commonly caused by viral and bacterial infections. Viral infections can have a dry cough, and the patient needs to be treated with antiviral medication. In the case of bacterial infections, a combination of antibiotic medications is required. Patients also need to undergo routine blood tests to clarify whether the infection is viral or bacterial, and they also need to be combined with cough and phlegm medications, such as tranylcypromine. Three month old babies avoid sudden cold and heat, keep warm and also give necessary hydration. Patients need to prevent colds and avoid the application of other medications.