The symptoms of cough and nasal congestion in 3-month-old babies require different treatment measures according to the specific situation: 1.To relieve the symptoms by drinking more water and applying hot compresses to the nose, nasal massage, etc. You can also clean the nasal scabs and adopt a lateral position, etc. This method can be used for children with mild symptoms, and you should also pay attention to keeping the child warm, pay attention to ventilation in the room, and the room temperature should be appropriate. 2.For children with severe symptoms of cough and nasal congestion, you should take medication to relieve the symptoms, For children with severe symptoms of cough and nasal congestion, it is clinically necessary to take medication to relieve the symptoms, and pediatric cough and phlegm granules can be taken to relieve the cough. 3. If frequent cough and phlegm symptoms occur, and the symptoms of nasal congestion are also severe, it is recommended that parents promptly take the child to seek medical treatment, and antibiotics, such as cefixime or antiviral oral solution, should be taken under the guidance of the doctor.