Excessive levels of liver enzymes in your blood may signal inflammation in your liver. Liver damage can be caused by a wide variety of factors, including alcohol abuse, long-term use of certain medications, viral hepatitis and autoimmune disorders. Milk thistle has been used for thousands of years to protect the liver. Consult your doctor before taking milk thistle supplements.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Your Liver Enzymes

Liver function tests measure four types of liver enzymes that are categorized into two classes, according to the author of "Dr. Melissa Palmer's Guide of Hepatitis and Liver Disease." The transaminases consist of aspartate aminotransferase, or AST, and alanine aminotransferase, or ALT 1. The cholestatic liver enzymes are alkaline phosphatase, or AP, and gamma-glutamyl transferase, or GGT. Elevated levels of transaminase liver enzymes are typically seen in patients with heart disease, liver tumors, and viral or drug and alcohol-induced hepatitis 1. Elevated levels of cholestatic liver enzymes may indicate drug or alcohol toxicity, as well as gallstones.

Milk Thistle's Active Ingredients

Extracts of milk thistle, or Silybum marianum, are produced from the fruit and seeds of the plant. The active compounds in milk thistle are silybin, silydianin and silychristin. Collectively, these compounds are grouped together and referred to as silymarin.

Specific Protective Effects

According to the University of Maryland Medical Center, milk thistle is the first line of defense to counteract the toxic effects of Amanita phalloides, a fungus commonly known as deathcap mushroom 4. Studies based on animal models have shown that milk thistle not only reduces the risk of death if administered within 24 hours, but all signs of toxicity disappear if given within 10 minutes. Milk thistle may improve liver function in patients with viral hepatitis and alcoholic cirrhosis, although more studies are needed to recommend the plant for these conditions, reports UMMC.

Evidence of Efficacy

According to a review published in a 2010 issue of "Phytotherapy Research," silymarin provides potent antioxidant activity. The authors conclude that silymarin prevents the binding of toxins to liver cell receptor sites. This activity is the primary mechanism of action with which milk thistle compounds prevent cell damage and subsequent “leakage” of liver enzymes into the bloodstream. Researchers reported in a 2010 issue of "Food and Chemical Toxicology" that ethanol milk thistle seed extracts reduced liver enzyme levels more effectively than the standard liver drug hepaticum.

Milk Thistle Contraindications

If you are pregnant or nursing, do not take milk thistle. Avoid the supplement if you have a history of a hormone-driven cancer, such as breast or prostate cancer. Milk thistle may interact with certain medications, including anti-seizure drugs, blood thinners and cholesterol-lowing medications.