If the five-month-old baby’s milk volume suddenly decreases, generally consider the following two situations: first, the baby is cold, gastrointestinal tract dysfunction resulting in a decrease in appetite, at this time the mothers can gently touch the baby’s tummy soft or not, to see if there is a manifestation of intestinal flatulence, because the baby’s age is relatively small, and gastrointestinal function is not well developed, easy to cause gastrointestinal tract dysfunction after being cold, including loss of appetite, bloating, constipation and other symptoms. Constipation and other symptoms, it is recommended to eat probiotics to regulate the gastrointestinal tract. Secondly, the baby has ulcers or herpes in the mouth, then the moms can open the baby’s mouth to see if there are small ulcers or herpes inside. If it is found to be an ulcer, it is recommended to take vitamin B2. You can add a small amount of montmorillonite with some water, make it into a puree and apply it to the mouth ulcer. If herpes is found, you can use ribavirin aerosol to spray the mouth, and pay special attention to whether the baby has other clinical manifestations, such as fever, vomiting, diarrhea, etc.. If these symptoms appear, it is recommended to visit the hospital promptly for an interview.