Breastfed children, the sour smell of stool, may be due to the high content of lactose in breast milk, coupled with the development of the baby’s gastrointestinal function is not very sound, so it affects the digestion and absorption of lactose, and undigested lactose will enter the baby’s large intestine, therefore, by some intestinal bacterial fermentation, there will be a sour smell of stool. There is another situation, after the baby added complementary food, the starch in the complementary food is not fully digested, and add complementary food irregularly, resulting in poor digestion of the child, the starch into the intestinal tract, which leads to sour stools, or bloating. For such a child, a small number of feedings should be used. The child’s abdomen needs to be massaged to improve gastrointestinal function. Oral intestinal microecological preparations can be taken to improve the intestinal microecological environment, such as Bifidobacterium bifidum, or Saccharomyces boulardii, or you can also give the child massage, or hot compresses on the abdomen, the effect is also good.