Generally, the causes of old exhaust in newborns mainly include the following two situations. First, due to constipation, if the stool is relatively dry, but the gastrointestinal tract peristalsis is normal, there will be old exhaust, because through the exhaust to promote the gastrointestinal tract peristalsis, the gastrointestinal tract stool excretion, but, because the stool is very dry, less water, so it is difficult to discharge the stool every time when the exhaust. Secondly, due to functional dyspepsia, if the child eats too much milk at one time, thus causing the gastrointestinal tract to be unable to digest and absorb effectively, the old exhaust will also occur, and other symptoms of dyspepsia such as bad breath and sour stools will often appear.