Chronic hepatitis C inflames the liver, which causes scarring that can eventually lead to cirrhosis, liver failure and possibly liver cancer. In an effort to protect the liver from these damaging processes, many people with hepatitis C try herbal remedies. Commonly used herbs include milk thistle, licorice root and astragalus, all of which have been shown to have antiinflammatory and/or antioxidant effects in laboratory studies and some preliminary studies in people. However, no herbs have been proved effective for hepatitis C treatment, and they cannot cure the disease.
Milk thistle is the most commonly used herb among people with hepatitis C in the United States. The medicinal component of milk thistle is silymarin, a mixture of chemicals extracted from the seeds. Silymarin exhibits antioxidant, antiinflammatory and antiviral effects in animal and laboratory studies. These properties could prove useful if they also occur in people with hepatitis C, which attacks and inflames liver cells. However, no lasting beneficial effects have yet been proved in people with hepatitis C.
An analysis of 5 studies examining the effects of silymarin in people with hepatitis C was published in August 2014 in "BioMed Research International." The researchers found that silymarin did not significantly reduce hepatitis C virus or liver enzyme levels -- a marker of liver inflammation. These findings suggest that the promising antiviral and antiinflammatory effects of silymarin seen in the laboratory have yet to be fully realized in human studies. However, the researchers found that study participants who took silymarin reported better physical functioning and less pain, compared to people not taking the herb.
Side effects are rare with recommended doses of milk thistle, although mild stomach upset, diarrhea and headaches can occur. Higher doses might cause more serious side effects.
Licorice root contains a compound called glycyrrhizin that exhibits antiviral, antiinflammatory and antioxidant properties in animal and laboratory studies. One laboratory study, published in "PLoS One" in July 2013, found that glycyrrhizin slowed hepatitis C virus production in infected cells. However, when intravenous glycyrrhizin was administered 3 to 5 times weekly for a year to people with hepatitis C, there was no reduction in the amount of virus in their bloodstream, reported the authors of an August 2012 "Journal of Viral Hepatitis" research report. While the intravenous glycyrrhizin did not show antiviral activity in the study, there was a reduction in liver enzyme levels that might indicate reduced liver inflammation. Notably, intravenous glycyrrhizin is not available in the United States, and the amount of glycyrrhizin the liver is exposed to from oral licorice root supplements is much lower than when the compound is administered intravenously.
Glycyrrhizin can cause high blood pressure and water and salt retention -- especially when taken in high doses or long-term. These side effects can be dangerous for people with liver, kidney or heart disease.
Astragalus root is commonly used in conjunction with other herbs in Eastern medicine. It has been shown to stimulate immune system cells and act as an antioxidant in animal and laboratory studies. These effects might help protect against cancer development -- a potential benefit for people with hepatitis C as the infection increases liver cancer risk. In a study published in the "Journal of Ethnopharmacology" in January 2014, researchers demonstrated that a combination of astragalus and the herb Salvia miltiorrhiza reduced the incidence of experimentally induced liver cancer in rats. Authors of an August 2009 "Journal of Experimental and Clinical Cancer Research" report examined the results of 45 Chinese studies in which various traditional Chinese medicine concoctions were used along with standard therapy to treat people with liver cancer. The researchers found that concoctions containing astragalus, ginseng and mylabris -- dried Chinese blister beetles -- conferred a treatment advantage. The authors noted, however, that the research methods were poor and rigorous studies are needed to determine whether any of these traditional Chinese medicines might benefit people with liver cancer.
Astragalus is generally considered safe. However, it may interfere with immune system suppressants taken by people who have had organ transplants, such as cyclosporine (Gengraf, Sandimmune) and tacrolimus (Astagraf XL, Prograf).
Herbal remedies are not a replacement for standard medical treatment for hepatitis C and can pose serious risks. Because liver function may be reduced, herbs might not be metabolized normally. Additionally, some herbs interact dangerously with anti-hepatitis C drugs and other medications. For example, people taking the direct-acting antiviral medicine simeprevir (Olysio) are cautioned against using milk thistle, as it may cause a buildup of the medication. On the flip side, St. John's wort can decrease the effectiveness of direct-acting antiviral medications used to treat hepatitis C.
Talk with your doctor before taking any herb to be sure it's safe for you. Also, tell each of your healthcare providers about all medicines, herbs and supplements you're taking. Seek medical help for unexplained, new or ongoing symptoms.
Medical advisor: Tina St. John, M.D.