It usually takes 3 days to be able to take levofloxacin after drinking alcohol to avoid causing a disulfiram reaction. Levofloxacin, a drug with a half-life of 7.6 hours in the human body, needs to undergo 7 half-lives before it can be fully metabolized in the body, so it is generally recommended that patients take levofloxacin for 3 days before drinking alcohol is safer. Levofloxacin is a kind of antibacterial drugs, once taken after drinking alcohol, may induce disulfiram reaction, causing headache, dizziness, nausea, vomiting and facial flushing and other clinical symptoms, and may even induce a decrease in blood pressure, chest tightness, panic, and shock and other reactions, which is dangerous to life. Common adverse effects of Levofloxacin include nausea, vomiting, insomnia, headache and dizziness, etc. It is contraindicated for those who are allergic to Levofloxacin or fluoroquinolones. The choice and use of drugs should be under the guidance of a doctor, not self-medication.