Don't drink alcohol while taking antibacterial drugs like cephalosporins or metronidazole, or for 7 days after stopping, and don't touch alcohol-containing medicines such as Huoxiang Zhengqi liquid (藿香正气水) or cough syrup

Cost

Free. Go without alcohol for a little over a week, and before taking other medicines, check whether the ingredients include ethanol.

What you get

This is called a disulfiram-like reaction. A 2023 safe-medication explainer from the Fujian Provincial Medical Products Administration (福建省药监局) says that drinking alcohol around the time of taking some cephalosporins may trigger this reaction, which “can seriously harm health or even endanger life.” Symptoms include facial flushing, sweating, palpitations, and even difficulty breathing, low blood pressure and anaphylactic shock. The explainer lists drugs according to the Clinical Medication Guide of the Pharmacopoeia of the People's Republic of China (《中华人民共和国药典临床用药须知》), including cefazolin, ceftriaxone, cefoperazone, metronidazole, tinidazole and furazolidone. It states “no alcohol, and no alcohol-containing drugs or foods, within 7 days after medication,” with liquor-filled chocolate and Huoxiang Zhengqi liquid as examples. The reason is that the enzyme the drug inhibits often takes 4 to 5 days to recover. A hospital in Guangzhou compiled 82 cases over 2 years. 57 (69.51%) were caused by cephalosporins and 10 (12.20%) by nitroimidazoles (metronidazole, tinidazole and the like). The alcohol came from alcoholic drinks in 40 cases (48.78%) and from ethanol-containing drugs in 31 cases (37.80%). The oral ones included Huoxiang Zhengqi liquid, cough syrup and motherwort fluid extract (益母草流浸膏). Of the 82 cases, 68 were mild, 9 moderate and 5 severe; they eased within 1 to 3 hours, and there were no deaths. The U.S. metronidazole label requires no alcohol during treatment and for at least 3 days after stopping, and no products containing propylene glycol.

Notes

Not every cephalosporin does this, but ordinary people can't tell them apart, so following this rule for whichever one you take is the easiest. When a doctor prescribes a cephalosporin or metronidazole, volunteer whether you have had alcohol in the last few days. That explainer suggests no drinking for 3 days before taking the drug as well, while admitting that no authoritative statement yet exists for that interval. If you flush and your heart pounds, stop whatever contains alcohol right away. The explainer says mild cases can ease on their own, and severe ones must be taken to a hospital. Don't drink alcohol while taking acetaminophen either; see §34.1 (acetaminophen). Graded B because the evidence is case compilations and package inserts, with no comparison group. The benefit is rated “small”: all 82 of those cases eased within hours, there were no deaths, and only 5 were severe.

Evidence grade

B : Supported by research but without a precise number, or based on small or single studies.

Sources

1. 福建省药品监督管理局（福建省药品科普与监管数据中心）(2023). 2023年“全国安全用药月”原创科普小知识——为什么吃头孢不能喝酒. https://yjj.scjgj.fujian.gov.cn/ztzl/kpzl/qgaqyyy/202312/t20231215_6334595.htm
2. 房财富, 涂星, 刘韬, 黄红兵, 邱孟, 梁蔚婷 (2015). 我院双硫仑样反应82例分析. 中国药房, 26(29):4089-4091. https://doi.org/10.6039/j.issn.1001-0408.2015.29.19
3. Pfizer (2026). FLAGYL 375 (metronidazole) capsules, prescribing information: Contraindications, Interaction with Alcohol. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a2883ca1-5a9a-4259-9d80-46ab67274384

Translated from the Chinese original. Original book, section 34, tip 11. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer