Probiotics should be selected according to different symptoms and different ages, children can use Bacillus licheniformis, Saccharomyces boulardii, etc. for diarrhea. Bifidobacteria and Lactobacillus can be used for constipation in middle-aged and old people. It is recommended to follow the doctor’s advice. If infants or children have diarrhea caused by bacteria or fungi, Saccharomyces boulardii and Bacillus licheniformis can be used as prescribed by the doctor. For chronic constipation caused by gastric insufficiency in middle-aged and old people, Bifidobacterium bifidum and Lactobacillus lactis can be taken orally according to doctor’s prescription. Probiotics such as Bacillus subtilis and Clostridium casei can be used for infants or children with functional indigestion. When taking probiotics, it is recommended to use lukewarm water to avoid losing the activity of probiotics with hot water. When using probiotics, you should consult a professional doctor and follow the doctor’s instructions, do not take medication on your own, so as not to delay your condition.