The first thing to do is to keep away from the allergens, feed the baby properly, and medicate the baby to improve the symptoms. 1. Stay away from allergens: babies with coughs and phlegm caused by allergies should find out the allergens of babies, such as pollen, eggs, shrimp, etc., and reduce the contact with allergens to avoid aggravation of the condition. 2. Appropriate water feeding: babies with allergies and coughing phlegm should be properly fed some warm water to dilute the phlegm, which is conducive to phlegm coughing, drink more water and urinate more often, which is conducive to the body’s garbage, toxins from the urine out. 3. medication: babies due to allergies caused by coughing with phlegm, can be under the guidance of the doctor anti-allergy drug treatment, such as oral cetirizine hydrochloride drops, chlorpheniramine maleate to relieve the symptoms. Infants with allergic cough with phlegm are advised to seek prompt medical attention. The above medications should be used under medical supervision.