Before taking two cold or pain relievers at the same time, check their ingredient lists — only one of them should contain acetaminophen.

Acetaminophen is present in many cold medicines. Taking two such products means you’re consuming double the dose, which can damage the liver. In the U.S., nearly 30% of patients suffering from acute liver failure due to acetaminophen never receive a liver transplant in time. Domestic instructions recommend a maximum daily intake of 2 grams, and alcohol should be avoided while taking this drug.

No cost at all. It only takes a minute or two to glance at the ingredient list on each package.

Over six years, 22 U.S. hospitals tracked 662 cases of acute liver failure. Of these, 275 (42%) were caused by acetaminophen; the median dose consumed was 24 grams. Among those 275 patients, 131 (48%) took the drug unintentionally. In 38% of those cases, they were also taking two or more other medications containing acetaminophen. Ultimately, 27% of these patients died before a transplant became possible, while 8% underwent liver transplantation. In 2020, China’s National Medical Products Administration mandated that OTC packaging clearly state excessive use can cause severe liver damage and that the daily limit is 2 grams. Packaging must also warn against combining this drug with other acetaminophen-containing or analgesic products. U.S. regulations require such OTC products to explicitly list three main risk factors: exceeding the daily limit, concurrent use with other acetaminophen-containing drugs, and drinking more than three alcoholic drinks daily while taking it.

Acetaminophen is also known as paracetamol. Cold medicines whose generic names contain the characters “anfen” — such as paracetamol pseudoephedrine or paracetamol caffeine chlorpheniramine — all contain this ingredient. When in doubt, bring all your medications to a pharmacist for review. This evidence grade is set at B because the U.S. data comes from case registries lacking a control group, so it’s impossible to calculate exactly how many adverse events could be prevented by checking ingredient lists. The “large” benefit rating is based on the severity of outcomes: nearly 30% of acute liver failure cases end in death.

Larson AM, Polson J, Fontana RJ, et al.; Acute Liver Failure Study Group (2005). Acetaminophen-induced acute liver failure: results of a United States multicenter, prospective study. Hepatology, 42(6):1364-1372. https://doi.org/10.1002/hep.20948；国家药监局关于修订对乙酰氨基酚常释及缓释制剂说明书的公告（2020年第15号）及附件1《对乙酰氨基酚常释制剂处方药说明书修订要求》、附件2《对乙酰氨基酚常释制剂非处方药说明书修订要求》、附件3《对乙酰氨基酚缓释制剂说明书修订要求》（湖南省药品监督管理局转载）. http://mpa.hunan.gov.cn/mpa/xxgk/tzgg/wjtz/202003/t20200311_11809335.html；21 CFR 201.326(a)(1)(iii)(A) Liver warning. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-C/part-201/subpart-G/section-201.326；Smilkstein MJ, Knapp GL, Kulig KW, Rumack BH (1988). Efficacy of oral N-acetylcysteine in the treatment of acetaminophen overdose: analysis of the national multicenter study (1976 to 1985). New England Journal of Medicine, 319(24):1557-1562. https://doi.org/10.1056/NEJM198812153192401；MedlinePlus. Acetaminophen (In case of emergency/overdose). https://medlineplus.gov/druginfo/meds/a681004.html