The reason why the baby coughs when it is cold or hot is physical and chemical stimulation, upper respiratory tract infection, you can use general treatment, medication, etc. to alleviate the disease. 1. Physical and chemical factors stimulation: when the alternation of hot and cold air, will cause irritation to the mucous membrane of the respiratory tract, and then the symptoms of coughing. In this case, you should ensure that the temperature and humidity are appropriate, and secondly, you should not breastfeed too much to avoid choking. If the coughing phenomenon is more serious, you can use amlodipine oral solution, propecia and other drugs to stop coughing. 2. Upper respiratory tract infection: Upper respiratory tract infection is mostly caused by viral infection, which will make the baby cough, fever and other conditions. During the onset of the disease, appropriate rehydration. Secondly, you also need to use Ambroxol oral solution to relieve cough. The baby’s body resistance is weakened, so it is easy to cough when it is cold or hot. It is recommended not to use medication blindly, but should seek medical advice as soon as possible and use medication under the guidance of healthcare professionals.