The liver is a marvelously sophisticated chemical laboratory, capable of carrying out thousands of chemical transformations on which the body depends. The liver produces important chemicals from scratch, modifies others to allow the body to use them better, and neutralizes an enormous range of toxins.

However, this last function of the liver, neutralizing toxins, is also the organ’s Achilles’ heel. The process of rendering toxins harmless to the body at large may bring harm to the liver itself.

Alcohol is the most common chemical responsible for toxic damage to the liver, causing fatty liver, alcoholic hepatitis, and, potentially, cirrhosis of the liver. Exposure to industrial chemicals may harm the liver. Many prescription medications may damage the liver as well, including cholesterol-lowering drugs in the statin family and high-dose niacin (also used to reduce cholesterol levels.) The over-the-counter drug acetaminophen (Tylenol) is highly toxic to the liver when taken to excess. Finally, numerous natural herbs and supplements contain chemicals that may cause or accelerate harm to the liver. (See Herbs and Supplements to Use Only With Caution below.)

Chemicals aren’t the only source of harm to the liver. Viruses may infect it, causing viral hepatitis; hepatitis C, in particular, may become chronic and gradually destroy the liver. In addition, during pregnancy, the liver may become backed up with bile, a condition called cholestasis of pregnancy.

Conventional treatment of liver disease depends on the source of the problem. People who abuse alcohol will at the very least avoid further liver damage by stopping alcohol use, and, in cases short of liver cirrhosis, full liver recovery may be expected. When drugs are at fault, it may be possible to switch to a different drug.

Conventional treatment of liver injury caused by chronic viral hepatitis involves sophisticated immune-regulating therapies, which have become fairly successful. In extreme cases of liver injury, a liver transplant may be necessary.

Natural treatments for alcoholic hepatitis, cirrhosis, and viral hepatitis are each discussed in their own articles. In this article, we discuss natural treatments for other forms of liver disease. In addition, we address the herbs and supplements that may harm the liver and that, therefore, should not be taken by people who already have liver disease.

Milk Thistle

The herb milk thistle has shown promise for a wide variety of liver conditions, and for this reason it is often said to have general liver protective properties.

Some evidence suggests benefit for viral hepatitis (especially chronic hepatitis), cirrhosis of the liver, alcoholic hepatitis, and liver toxicity caused by industrial chemicals, mushroom poisons, and medications.1-25 However, as yet the evidence that milk thistle really works remains incomplete and contradictory.

For example, a double-blind, placebo-controlled studyperformed in 1981 followed 106 Finnish soldiers with alcoholic liver disease over a period of 4 weeks.18 The treated group showed a significant decrease in elevated liver enzymes and improvement in liver histology (appearance of cells under a microscope), as evaluated by biopsy in 29 subjects.

Two similar studies provided essentially equivalent results.9,11 However, a 3-month, randomized, double-blind study of 116 people showed little to no additional benefit, perhaps because most participants reduced their alcohol consumption and almost half stopped drinking entirely.20Another study found no benefit in 72 patients followed for 15 months.7

Study results similarly conflict on whether milk thistle is helpful in liver cirrhosis.

In a double-blind, placebo-controlled study of 170 people with alcoholic or non-alcoholic cirrhosis, researchers found that the 4-year survival rate was 58% in the group treated with milk thistle as compared to only 38% in the placebo group.10 This difference was statistically significant.

A double-blind, placebo-controlled trial that enrolled 172 people with cirrhosis for 4 years also found reductions in mortality, but they just missed the conventional cutoff for statistical significance.4Yet another study, a 2-year, double-blind, placebo-controlled trial of 200 people with alcoholic cirrhosis, found no reduction in mortality attributable to the use of milk thistle.1

Other double-blind studies of people with cirrhosis have found improvements in tests of liver function,6,16although one did not.3

A 2007 review of published and unpublished studies on milk thistle as a treatment for liver disease concluded that benefits were seen only in low-quality trials, and, even in those, milk thistle did not show more than a slight benefit.56

Milk thistle is also used in a vague condition known as minor hepatic insufficiency, or "sluggish liver."26 This term is mostly used by European physicians and American naturopathic practitioners—conventional physicians in America don't recognize it. Symptoms are supposed to include aching under the ribs, fatigue, unhealthy skin appearance, general malaise, constipation, premenstrual syndrome, chemical sensitivities, and allergies.

For more information, including dosage and safety issues, see the full Milk Thistle article.


The body manufactures S-adenosylmethionine (SAMe) for use in converting certain chemicals to other chemicals (specifically, through the processes of transmethylation and transsulfuration). Some evidence suggests that SAMe taken as an oral supplement may have value in the treatment of various liver diseases, including chronic viral hepatitis, liver cirrhosis, jaundice of pregnancy, and liver toxicity caused by drugs or chemicals.27-31,51-54

Perhaps the best evidence regards cholestasis (backup of bile in the liver) caused by serious liver disease. In a 2-week, double-blind study of 220 people with cholestasis, use of SAMe (1,600 mg daily) significantly improved liver-related symptoms as compared to placebo.28 Most participants in this study had chronic viral hepatitis.

Another large study evaluated the potential benefits of SAMe for the treatment of people with alcoholic liver cirrhosis.27 This 2-year, double-blind, placebo-controlled study of 117 people failed to find SAMe helpful for the group as a whole. However, in a subgroup of those with less advanced disease, treatment with SAMe appeared to reduce the number of people who needed a liver transplant, or who died.

Gilbert’s syndrome is an unexplained but harmless condition in which levels of bilirubin rise in the body, causing an alarming yellowing of the skin (jaundice). Weak evidence hints that SAMe may help reduce bilirubin levels in this condition.32

For more information, including dosage and safety issues, see the full SAMe article.