The reason for the sudden decrease in the baby’s milk supply may be anorexia, dyspepsia, acute gastroenteritis and so on. 1. anorexia: some babies in 4-6 months will appear anorexia, there may be a sudden decrease in the amount of milk, is a physiological, after a month will generally be restored. 2. indigestion: the baby’s gastrointestinal function has not yet developed, the feeding method must pay attention to, if it is not appropriate, there may be indigestion, which can also make the baby’s milk volume decreased. 3. Acute gastroenteritis: due to their own digestive function is not perfect, it is easy to appear acute gastroenteritis, at this time it is easy to appear the situation of the milk volume, this is a pathology, need to go to the hospital, parents must pay attention to avoid the occurrence of adverse events. The baby suddenly appeared to reduce the amount of milk, parents must pay attention to, timely go to the hospital pediatric consultation to clarify the cause of the disease.