Acetaminophen is widely used to reduce pain and fever.
The herb milk thistle and the supplements coenzyme Q 10 (CoQ 10) and methionine might help protect the liver against damage caused by excessive use of acetaminophen.1–3 However, it is extremely dangerous to take excessive amounts of acetaminophen, and we certainly wouldn't count on any of these supplements to protect you from harm if you do so!
One study from the 1970s suggests that very high doses of vitamin C (3 g daily) might increase the levels of acetaminophen in the body.4 This could potentially put you at higher risk for acetaminophen toxicity. You probably don't need to be overly concerned if you take acetaminophen in recommended doses now and then for pain or fever. However, a problem might occur if you take higher-than-recommended doses or if you take high doses of acetaminophen on a regular basis, such as for osteoarthritis. The risk increases if you have liver or kidney impairment or if you drink alcoholic beverages regularly, which taxes the liver even more.
The herbs chaparral ( Larrea tridentata or L. mexicana), comfrey (Symphytum officinale), and coltsfoot (Tussilago farfara) contain liver-toxic substances. Combined use with acetaminophen could accentuate the liver toxicity of the medication.
Potassium citrate, sodium citrate, and potassium-magnesium citrate are sometimes used to prevent kidney stones. These supplements reduce urinary acidity, and can therefore lead to decreased blood levels and effectiveness of acetaminophen.5
1. Muriel P, et al. Silymarin protects against paracetamol-induced lipid peroxidation and liver damage. J Appl Toxicol. 12:439–442;1992.
2. Li H, et al. Preventive effect of coenzyme Q 10 on hepatic damage caused by overdosage of paracetamol in mice. Zhongguo Yaolixuie Yu Dulixue Zaxhi. 11:278–280;1997.
3. Neuvonen PJ, Tokola O, Toivonen ML, and Simell O. Methionine in paracetamol tablets, a tool to reduce paracetamol toxicity. Int J Clin Pharmacol Ther Toxicol. 23:497–500;1985.
4. Houston JB and Levy G. Drug biotransformation interactions in man. VI: Acetaminophen and ascorbic acid. J Pharm Sci. 65:1218–1221;1976.
5. Tatro D, ed. Drug Interaction Facts. St. Louis, Mo: Facts and Comparisons; 1999.
Last reviewed December 2015 by EBSCO CAM Review Board Last Updated: 12/15/2015