Cough in three-month-old infants can be seen in physiological phenomena, pathological conditions (such as acute bronchitis), the need for medication needs to be decided according to the cause of the cough, such as acute bronchitis caused by the need for oral drug intervention. 1. Physiological phenomenon: cough is the body’s normal protective mechanism, can make the respiratory tract secretion discharge. When the baby sleeps and wakes up in the morning, the above phenomenon can occur, often coughing lightly, the baby’s general condition is good, no other abnormal symptoms such as fever, wheezing, etc., is a normal physiological phenomenon, no oral drug treatment. 2. Condition: such as acute bronchitis, clinical cough, cough can show progressive aggravation, can be dry cough, or sputum, cough sputum, etc., some babies will also be accompanied by fever or wheezing symptoms, improve the chest X-ray examination can assist in the diagnosis. Such babies require active therapeutic intervention, with oral medication under the guidance of a specialist, and intravenous fluids may be required if necessary. Coughing in a three-month-old baby is just a symptom, and the specific cause of the cough should be clarified in time, so that the treatment of the cause of the cough is the fundamental treatment, and the specific treatment should be in accordance with the doctor’s instructions.