Rehydration salts are not needed for normal people. They are usually given to patients with severe diarrhea, resulting in electrolyte and water deficiency, and there are no good conditions for infusion at this time. Of course, if the patient has obvious nausea and vomiting, along with water and electrolyte disorders, because there is no way to replenish rehydration salts, drinking them will cause nausea and vomiting, and they may be poorly absorbed when they are taken. Therefore, when a patient does not have severe nausea and vomiting, but also has water and electrolyte disturbances due to diarrhea, rehydration salts are still very effective.