The use of Levofloxacin Mesylate Injection requires a doctor to determine the dose in conjunction with the severity of the patient’s condition during clinical treatment. Generally speaking, the single dose for adults with normal renal function is 250 mg or 500 mg. It is first dissolved with 5~10ml of 0.9% sodium chloride injection, then added to 100ml saline for intravenous drip and used every 24 hours. Or a slow intravenous drip of 750 mg, ending with a 100 ml saline flush. For children under 18 years of age, the dose is 500mg per dose for children weighing more than 50 kg.Children under 50 kg need to be treated according to their body weight at a dose of 8mg/kg, not exceeding 250mg per dose. Levofloxacin Mesylate Injection is a new generation of quinolones. It has strong antibacterial activity against most anaerobic, gram-positive or gram-negative bacteria. Common adverse reactions are nausea, vomiting, headache, dizziness, insomnia, etc. Serious adverse reactions include tendonitis and tendon rupture, worsening of myasthenia gravis, and hypersensitivity reactions. However, the drug must be used under the supervision of a physician to avoid adverse effects.