40 days baby spitting up frequently can be seen in physiological phenomena, pathological conditions (such as gastrointestinal dysfunction, acute enteritis), specific need to analyze and judge according to the baby’s situation. 1. Physiological phenomenon: for 40-day-old babies, the digestive system is not well developed, the esophagus and cardia sphincter function is weak, the stomach is horizontal, easy to spit up, is a normal physiological phenomenon, coupled with improper feeding, such as feeding when crying, or breastfeeding process is too fast too fast, the phenomenon of frequent spitting up can occur. 2. Pathological phenomena (1) Gastrointestinal dysfunction: If there is improper feeding or overfeeding, the digestive tract cannot tolerate it, the above manifestations may occur, and some of them may have vomiting, abdominal distension and other discomforts. (2) Acute enteritis: mostly caused by viral or bacterial infections, frequent spitting up can occur, and some of them may vomit, accompanied by diarrhea, abdominal pain and other manifestations, and in severe cases, dehydration can occur. (3) other: such as sepsis and other more serious diseases, there can be general discomfort, affecting gastrointestinal function, spitting up frequently, depression or fever and other manifestations. 40 days baby spitting up frequently may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.