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Cancer Health Center

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Milk Thistle (PDQ®): Complementary and alternative medicine - Health Professional Information [NCI] - Adverse Effects


Theoretically, milk thistle may also interact adversely with chemotherapy drugs that exert their cytotoxic effects through the generation of free radicals. Silymarin and its metabolite inhibit P-glycoprotein-mediated cellular efflux, leading to the potentiation of doxorubicin cytotoxicity.[9] No trials have been performed to support or negate these theoretical considerations. No effects on indinavir and alcohol pharmacokinetics have been observed. Enhancement of antiarrhythmic effects of amiodarone in rats has been observed.[9]


  1. PDR® for Herbal Medicines™. 2nd ed. Montvale, NJ: Medical Economics, 2000.
  2. An adverse reaction to the herbal medication milk thistle (Silybum marianum). Adverse Drug Reactions Advisory Committee. Med J Aust 170 (5): 218-9, 1999.
  3. Vailati A, Aristia L, Sozzé E, et al.: Randomized open study of the dose-effect relationship of a short course of IdB 1016 in patients with viral or alcoholic hepatitis. Fitoterapia 64 (3), 219-28, 1993.
  4. Hernández R, Nazar E: [Effect of silymarin in intrahepatic cholestasis of pregnancy (preliminary communication)] Rev Chil Obstet Ginecol 47 (1): 22-9, 1982.
  5. Hruby K, Csomos G, Fuhrmann M, et al.: Chemotherapy of Amanita phalloides poisoning with intravenous silibinin. Hum Toxicol 2 (2): 183-95, 1983.
  6. Venkataramanan R, Ramachandran V, Komoroski BJ, et al.: Milk thistle, a herbal supplement, decreases the activity of CYP3A4 and uridine diphosphoglucuronosyl transferase in human hepatocyte cultures. Drug Metab Dispos 28 (11): 1270-3, 2000.
  7. Zuber R, Modrianský M, Dvorák Z, et al.: Effect of silybin and its congeners on human liver microsomal cytochrome P450 activities. Phytother Res 16 (7): 632-8, 2002.
  8. van Erp NP, Baker SD, Zhao M, et al.: Effect of milk thistle (Silybum marianum) on the pharmacokinetics of irinotecan. Clin Cancer Res 11 (21): 7800-6, 2005.
  9. Hu Z, Yang X, Ho PC, et al.: Herb-drug interactions: a literature review. Drugs 65 (9): 1239-82, 2005.

This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at http:// cancer .gov or call 1-800-4-CANCER.

WebMD Public Information from the National Cancer Institute

Last Updated: 8/, 015
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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