Baby dilute watery stools may be rotavirus, virulence-producing bacterial infections, need to use montelukast, probiotics, rehydration solution and other treatments. 1. Rotavirus: the most common etiology of infantile diarrhea, mostly occurring in the fall, the virus invades the intestinal tract after replication, so that the small intestinal villi at the tip of the columnar epithelial cell degeneration, necrosis, damage to its reabsorption capacity, intestinal fluid accumulation and cause yellow watery or egg-shaped stool. If the number of diarrhea is high, the baby needs intravenous rehydration treatment for symptoms of dehydration. 2. Toxin-producing bacteria: such as Vibrio cholerae, enterotoxin-producing Escherichia coli, etc., mostly occurring in the summer, the pathogen invades the intestinal tract to release two kinds of enterotoxins, inhibit the small intestinal villi epithelial cells to absorb Na ⁺, Cl- and water, and promote the secretion of Cl-, resulting in a watery diarrhea. Oral montelukast adsorption of pathogens to enhance the barrier and Bacillus subtilis dictyostelium to regulate the intestinal flora can be administered. All of the above medications should be used under the supervision of a physician and should not be self-administered.