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Red Yeast Rice



Red yeast rice is bright reddish-purple fermented rice which is used as a dietary supplement, predominantly as a cholesterol lowering agent.  The reddish-purple color derives from the mold Monascus purpureus.  Red yeast rice use has been associated with very rare instances of acute, clinically apparent liver injury.



Red yeast rice is a traditional Chinese medicine used as an aid to digestion and revitalizing agent.  More recently, red yeast rice was shown to have a cholesterol lowering effect and was marketed as a natural means of treating hyperlipidemia.  However, chemical characterization of the components of red yeast rice (monascus purpureus) demonstrated the presence of several monacolins, one of which (monacolin K) is chemically identical to lovastatin, a commercially available HMG-coenzyme A inhibitor widely used in the management of hyperlipidemia.  While concentrations of lovastatin in commercial preparations of red yeast rice extract are variable, some have pharmacologically active concentrations of lovastatin.  Controlled trials have shown that red yeast rice extract can lower total serum and LDL cholesterol.  However, these same preparations have also been linked to rare cases of myopathy and liver injury similar to what occurs with lovastatin.  Red yeast rice extracts are available over-the-counter in multiple formulations and with variable concentrations of monacolins.  The FDA has ruled that red yeast rice extracts that have more than trace amounts of monacolin K (lovastatin) cannot be sold as a dietary supplement, but some products with detectable levels of lovastatin are commercially available.  The other components of red yeast rice may have independent effects of lipid levels.



In prospective controlled trials, red yeast rice extract formulations have not been associated with serum enzyme elevations or clinically apparent liver injury.  However, there have been isolated case reports of liver injury in patients on red yeast rice extracts.  A proportion of patients with liver injury attributed to red yeast rice extract were reported to have similar episodes of serum enzyme elevations during conventional lovastatin therapy.


Mechanism of Injury

Both the liver injury and myopathies attributed to red yeast rice extracts are probably due to the presence of lovastatin in concentrations of 1 to 10 mg per tablet.  Lovastatin is metabolized in the liver via CYP 3A4 and its liver injury is likely due to a toxic or immunogenic metabolite.


Outcome and Management

The reported cases of liver injury attributed to red yeast rice have been mild-to-moderate in severity and self-limited in course.  There have been no cases of acute liver failure or vanishing bile duct syndrome attributed to red yeast rice.  Persons with liver injury attributed to red yeast rice extracts should avoid exposure to lovastatin, but switching to other statins may be safe, although it should be done with caution.


Drug Class:  Herbal and Dietary Supplements


See also:  Lovastatin


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Red Yeast Rice


Red Yeast Rice – Generic


Herbal and Dietary Supplements



Fact Sheet at National Center for Complementary and Integrative Health, NIH


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Red Yeast Rice
Monacolin K
R400000000 Unspecified Not Applicable

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Red Yeast Rice


References updated: 10 January 2014


  1. Zimmerman HJ. Unconventional drugs. Miscellaneous drugs and diagnostic chemicals. In, Zimmerman HJ. Hepatotoxicity: the adverse effects of drugs and other chemicals on the liver. 2nd ed. Philadelphia: Lippincott, 1999, pp. 731-4.  (Expert review of hepatotoxicity published in 1999; several herbal medications are discussed, but not red yeast rice).

  2. Seeff L, Stickel F, Navarro VJ. Hepatotoxicity of herbals and dietary supplements. In, Kaplowitz N, DeLeve LD, eds. Drug-induced liver disease. 3rd ed. Amsterdam: Elsevier, 2013, p. 631-58.  (Review of hepatotoxicity of herbal and dietary supplements [HDS]; red yeast rice is not discussed).

  3. Stedman C. Herbal hepatotoxicity. Semin Liver Dis 2002; 22: 195-206. PubMed Citation  (Review and description of patterns of liver injury, including discussion of potential risk factors, and herb-drug interactions).

  4. Keithley JK, Swanson B, Sha BE, Zeller JM, Kessler HA, Smith KY. A pilot study of the safety and efficacy of cholestin in treating HIV-related dyslipidemia. Nutrition 2002; 18: 201-4. PubMed Citation  (In a controlled trial of cholestin [~5 mg of lovastatin] vs placebo for 8 weeks in 12 patients with hyperlipidemia, there were no changes in "hepatic function").

  5. Roselle H, Ekatan A, Tzeng J, Sapienza M, Kocher J. Symptomatic hepatitis associated with the use of herbal red yeast rice. Ann Intern Med 2008; 149: 516-7. PubMed Citation  (62 year old woman developed fever, nausea and fatigue 4 months after starting red yeast rice extract [ALT 211 U/L, bilirubin and Alk P not given], resolving within several months of stopping).

  6. Grieco A, Miele L, Pompili M, Biolato M, Vecchio FM, Grattagliano I, Gasbarrini G. Acute hepatitis caused by a natural lipid-lowering product: when "alternative" medicine is no "alternative" at all. J Hepatol 2009; 50: 1273-7. PubMed Citation  (63 year old woman with ALT elevations after 6 months of lovastatin use, developed fatigue 6 months after starting a cholesterol lowering herbal preparation containing red yeast rice extract [bilirubin 1.9 mg/dL, ALT 1760 U/L, Alk P 722 U/L], resolving over the next 6 months, but with persistence of ALT elevations).

  7. Chalasani N, Fontana RJ, Bonkovsky HL, Watkins PB, Davern T, Serrano J, Yang H, Rochon J; Drug Induced Liver Injury Network (DILIN). Causes, clinical features, and outcomes from a prospective study of drug-induced liver injury in the United States. Gastroenterology 2008; 135: 1924-34. PubMed Citation   (Among 300 cases of drug induced liver disease in the US collected between 2004 and 2008, 9% of cases were attributed to herbal medications, but no case was attributed to red yeast rice).

  8. Navarro VJ. Herbal and dietary supplement hepatotoxicity. Semin Liver Dis 2009; 29: 373-382. PubMed Citation   (Overview of the regulatory environment, clinical patterns, and future directions in research with HDS; red yeast rice is not listed as a potential hepatotoxin).

  9. Jacobsson I, Jönsson AK, Gerdén B, Hägg S. Spontaneously reported adverse reactions in association with complementary and alternative medicine substances in Sweden. Pharmacoepidemiol Drug Saf 2009; 18: 1039-47. PubMed Citation  (Review of 778 spontaneous reports of adverse reactions to herbals to Swedish Registry; no instance was linked to red yeast rice extracts).

  10. Becker DJ, Gordon RY, Halbert SC, French B, Morris PB, Rader DJ. Red yeast rice for dyslipidemia in statin-intolerant patients: a randomized trial. Ann Intern Med 2009; 150: 830-9. PubMed Citation  (Controlled trial of red yeast rice extract vs placebo in 62 patients who had stopped statin therapy because of myalgias, found similar rates of myalgias [7% vs 3%] and no change in ALT or AST levels in both groups).

  11. Halbert SC, French B, Gordon RY, Farrar JT, Schmitz K, Morris PB, Thompson PD, et al. Tolerability of red yeast rice  (2,400 mg twice daily) versus pravastatin  (20 mg twice daily) in patients with previous statin intolerance. Am J Cardiol 2010; 105: 198-204. PubMed Citation  (43 patients with myalgias due to statin use were treated with pravastatin or red rice extract for 24 weeks; discontinuation due to myalgias occurred in 5% on red yeast rice extract and 9% on pravastatin, and mean ALT levels were similar between the 2 groups).

  12. Venero CV, Venero JV, Wortham DC, Thompson PD. Lipid-lowering efficacy of red yeast rice in a population intolerant to statins. Am J Cardiol 2010; 105: 664-6. PubMed Citation  (Retrospective analysis of 25 patients who were treated with red yeast rice extract for hyperlipidemia; 2 patients had ALT elevations before treatment, which persisted during follow up, but were never >2 times ULN).

  13. Reuben A, Koch DG, Lee WM; Acute Liver Failure Study Group. Drug-induced acute liver failure: results of a U.S. multicenter, prospective study. Hepatology 2010; 52: 2065-76. PubMed Citation   (Among 1198 patients with acute liver failure enrolled in a US prospective study between 1998 and 2007, 133 [11%] were attributed to drug induced liver injury, of which 12 [9%] were due to herbals, including several herbal mixtures, usnic acid, Ma Huang, black cohosh, and Hydroxycut, but not red yeast rice).

  14. Gordon RY, Cooperman T, Obermeyer W, Becker DJ. Marked variability of monacolin levels in commercial red yeast rice products: buyer beware! Arch Intern Med 2010; 170: 1722-7. PubMed Citation  (Among 12 red yeast rice extracts commercially available in the US, total monacolin concentrations varied from 0.3-11.1 mg/capsule, monacolin K by 0.1-10.1 mg/capsule, and citrinin [which is nephrotoxic] was present in 4).

  15. Yang CW, Mousa SA. The effect of red yeast rice(Monascus purpureus) in dyslipidemia and other disorders. Complement Ther Med 2012; 20: 466-74. PubMed Citation  (Review of literature on efficacy of red yeast rice products found 22 clinical trials; no discussion of safety, ALT elevations or hepatotoxicity).

  16. Teschke R, Wolff A, Frenzel C, Schulze J, Eickhoff A. Herbal hepatotoxicity: a tabular compilation of reported cases. Liver Int 2012; 32: 1543-56. PubMed Citation  (A systematic compilation of all publications on the hepatotoxicity of specific herbals identified 185 publications on 60 different herbs, herbal drugs and supplements; one implicated red yeast rice [Roselle 2008]).

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Red Yeast Rice


  1. PubMed logoRecent References on Red Yeast Rice

  2. Clinical Trials logoTrials on Red Yeast Rice

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