Patients who experience gastrointestinal reactions such as nausea, vomiting, or diarrhea after taking metformin are advised to reduce or discontinue the dose. If the patient’s symptoms are tolerable, it is recommended to start metformin in small doses and take it during or immediately after meals to reduce gastrointestinal reactions. If the gastrointestinal response is mild on a small dose, the dose of metformin can be gradually increased until the patient tolerates it, depending on the blood glucose level. Patients with significant gastrointestinal symptoms who cannot tolerate metformin should discontinue the drug as soon as possible.