For infants and toddlers whose digestive systems are not yet fully developed, diarrhea always grows with them. When parents manage their children’s health, it is important not to be concerned, but to simply judge the symptoms before seeking medical attention. To determine the severity of diarrhea in infants and toddlers and the need for medication, it is important to look not only at the increase in the number of stools, but also at the increase in stool volume and changes in the nature of the stool. The common symptoms of diarrhea are divided into two categories in general: physiological and pathological. In physiological diarrhea, the baby only has an increase in the number of bowel movements, which generally does not require medication. Some babies with physiological diarrhea excrete yellow-green loose stools soon after birth, and the number of stools is also high, but they are in good spirits, they do not vomit, their appetite is always good, and their weight shows a trend of daily increase, and the diarrhea will disappear naturally as they grow older and add complementary foods. There is another type of diarrhea that is caused by bacteria, viruses or molds, called “pathological diarrhea”. Most infants and children with this type of diarrhea have fever, foul-smelling stools containing mucus or pus and blood, and if left untreated, the diarrhea will continue to worsen, leading to severe dehydration and shock. Diarrhea caused by different pathogens has its own characteristics. Diarrhea caused by pathogenic Escherichia coli can develop all year round, but the incidence is highest in May to August. Most children start with no fever, little vomiting, and a small number of diarrhea, and then become heavy with fever, intense vomiting, frequent stools, and soon dehydration, and the stools are mainly egg-flake soup-like, containing mucus, with a fishy odor. Diarrhea caused by viruses mostly occurs in August to November, often accompanied by upper respiratory tract infection, the stool is white rice soup-like or egg-flake soup-like, with a small amount of mucus, but no fishy odor. Diarrhea caused by mycobacteria stools are yellow thin or green, foamy, with mucus, tofu crumb-like, usually weak, malnourished or long-term antibiotics for children, easy to occur. When the above pathological symptoms appear, the baby needs to be sent to the hospital in time to avoid delaying the disease.