Healthy three-month-old babies breathe about 30 to 40 times a minute, which is within the normal range, lower or higher than the normal value is a pathological condition, you need to find out the cause of the symptomatic treatment. Three-month-old babies breathing fast, generally in 30 ~ 40 times / minute, lower than the normal range of sepsis, acute left heart failure, severe pneumonia and other conditions, need to improve the blood routine, blood culture, cardiac enzyme spectrum, chest X-ray and other related examinations to clarify the condition. Below normal range can be seen in febrile diseases, such as acute upper respiratory tract infection, bronchopneumonia and other infectious diseases, babies mostly have symptoms of the original disease, such as coughing, runny nose and other symptoms; other systemic diseases can also lead to respiratory increase, such as electrolyte disorders caused by acute gastroenteritis can lead to respiratory acceleration. Therefore, if the baby’s respiratory increase, it is recommended to go to the hospital in a timely manner to clarify the condition and give symptomatic treatment.