Norfloxacin is a fluoroquinolone antibacterial drug that affects cartilage development. It should be used with caution in pregnant and lactating women, and is not suitable for children and adolescents under 18 years of age. Gastrointestinal reactions are common during the use of this drug, which may manifest as abdominal discomfort or pain, diarrhea, nausea or vomiting, and generally do not require discontinuation of the drug and can gradually subside on their own, but patients with a history of gastric ulcer should be used with caution. Some patients may experience elevated serum aminotransferase, increased blood urea nitrogen and decreased peripheral blood leukocytes, which are mostly mild and may return to normal after discontinuation of the drug. A few patients may experience dizziness, headache, drowsiness or insomnia and peripheral nerve irritation, and a pins-and-needles sensation in the skin of the extremities or a slight burning sensation, which can be alleviated with the addition of vitamin B1 and B2. Allergic reactions such as rash, skin pruritus, occasionally exudative erythema multiforme and angioneurotic edema may occur. A small number of patients have photosensitivity reactions. Occasionally, seizures, psychiatric abnormalities, agitation, disturbance of consciousness, hallucinations, tremors may occur. High doses can cause crystalluria and occasionally hematuria. At present, Escherichia coli resistance to norfloxacin is common. Urine specimens should be taken for culture before administration, and the drug use should be adjusted with reference to the bacterial drug sensitivity results.