The role of oral rehydration salts is mainly to rehydrate and prevent or treat water-electrolyte disorders, and is usually used in patients with diarrhea. Rehydration salts are composed mainly of glucose, sodium chloride, potassium chloride, and sodium bicarbonate and are used to prevent and correct acid-base imbalance in the treatment of diarrhea. Patients with diarrhea usually lose not only water but also a lot of electrolytes causing a series of symptoms. However, rehydration salts are only symptomatic treatment, and the cause of the diarrhea needs to be clarified, whether it is bacterial enteritis or antibiotic-associated diarrhea or some other cause. If it is bacterial enteritis, oral antibiotics and antidiarrheal and astringent drugs should be taken, and if necessary, stool tests should be performed to check the bacterial and coccus ratios, and probiotics should be added to regulate the dysbiosis of the intestinal flora. If it is antibiotic-associated diarrhea, it is necessary to stop antibiotics and treat with antidiarrheal drugs.