Diuretic side effects include decreased blood pressure and electrolyte disorders. Specific types of side effects can vary, for example, spironolactone, a potassium-preserving diuretic, does not have hypokalemia, whereas hydrochlorothiazide, a thiazide, can cause hypokalemia. Diuretics can be divided into thiazides (e.g. hydrochlorothiazide, chlorothiazide), medullary diuretics (e.g. furosemide), potassium-preserving diuretics (e.g. spironolactone), and osmotic diuretics (e.g. mannitol). 1. Thiazides: there may be hypotension, low potassium and hyponatremia, renal function impairment. 2. Medullary diuretics: gastrointestinal discomfort (e.g., nausea, abdominal distension), hypotension, hypokalemia and hyponatremia, ototoxicity. 3. Potassium-preserving diuretics: hypotension, hyperkalemia, etc. 4. Osmotic diuretics: hyponatremia, dehydration, etc. For the application of diuretics, it should be standardized under the guidance of professional doctors.