The reasons why four-month-old babies don’t poop include physiological factors such as improper feeding, pathological factors such as constipation, intestinal obstruction, and common treatments include changes in feeding methods, medication, and surgical treatments. 1. Physiological factors: four months baby gastrointestinal function is not yet well developed, if feeding improperly, such as artificial feeding formula brewing concentration is high, can cause gastrointestinal dysfunction, caused by the phenomenon of not pooping, so usually breastfeeding mothers should be a light diet, formula brewing should be proportionate, according to the need to feed, appropriate can feed water. 2. constipation: the dry environment, too much milk, no proper water will cause the baby intestinal moisture, thus the phenomenon of not pooping, you can give the baby appropriate water, oral probiotics (such as Bacillus subtilis bacillus granules) to regulate the intestinal flora. 3. Intestinal obstruction: baby intestinal obstruction can be manifested as crying, vomiting, not pooping and other phenomena, conservative treatment of the symptoms have not been reduced, or even aggravated, should be timely surgical treatment. The above is a common way to deal with the baby does not poop, when the symptoms are not relieved, take the baby to the hospital in time to do the relevant examination, in addition to note that the above drugs are recommended to be taken under the guidance of a doctor, can not be used on their own.