If a patient is taking cephalosporin, it is recommended that 7 days elapse before consuming beer. Cephalosporin antibiotics can inhibit the activity of acetaldehyde dehydrogenase, leading to the accumulation of acetaldehyde, a metabolite of ethanol, in the body, producing a disulfiram-like chemical reaction. When the disulfiram-like reaction occurs, patients mainly show flushing, panic, rash, precordial pain, nausea, vomiting, and may even suffer from impaired consciousness and hypotensive shock, which may endanger their lives. Therefore, it is strictly forbidden to drink alcohol while taking cephalosporin, and because the metabolic rate of cephalosporin varies among individuals, it is clinically recommended that it is safer to drink beer 7 days after taking cephalosporin. Also, alcohol should not be consumed before 7 days of taking cephalosporins. In addition, if a patient inadvertently drinks alcohol while taking cephalosporin, he or she should quickly seek medical attention at the emergency room after a toxic reaction occurs.