Norfloxacin is also an antibiotic of the quinolone class and is mainly used to treat urinary tract infections or upper respiratory tract infections. Crystalluria can occur when this product is applied in large doses or when the urine pH is above 7. To avoid the occurrence of crystalluria, it is advisable to drink more water and keep the urine output above 1200ml in 24 hours. In cases of reduced renal function, the dose of the drug should be adjusted according to the renal function. Moderate and severe photosensitivity reactions can occur with the application of fluoroquinolones. Avoid excessive exposure to sunlight when applying this product, and discontinue the drug if photosensitivity reactions occur. Glucose-6-phosphate dehydrogenase deficient patients may experience hemolytic reactions on rare occasions. Quinolones, including this product, can cause worsening of myasthenia gravis symptoms and life-threatening respiratory muscle weakness. Special caution should be exercised in the use of quinolones including this product in patients with myasthenia gravis. In case of hepatic decompensation, such as severe (cirrhotic ascites), drug clearance may be reduced and blood concentration may be increased, especially in those with hepatic and renal decompensation, which should be applied after weighing the pros and cons and dose adjustment. It is prohibited for those who are allergic to norfloxacin.