When a 4-month-old baby sneezes and has a runny nose when receiving treatment, the first thing to do is to clarify the specific cause of the disease, such as viral colds, allergic rhinitis and so on, and then choose the appropriate medication for treatment. You can’t treat blindly, so as not to take the wrong medicine. 1. viral cold: 4 months baby sneezing runny nose is caused by viral cold, mild when you can not use medicine, but pay attention to the baby’s body to keep warm, but also to let the baby drink more water, so as to help relieve the condition. When it is serious, it needs to be treated with medication under the guidance of a doctor, such as antiviral oral solution. 2. Allergic rhinitis: sneezing and runny nose caused by allergic rhinitis should be checked for allergens, and those with clear allergens can alleviate the symptoms by avoiding contact with allergens. Parents are not recommended to give medication to their babies privately, and are advised to bring their babies to the hospital in time and choose the appropriate medication under the guidance of the doctor.