Milk thistle has been used medicinally for over 2000 years, most commonly for the treatment of liver and gallbladder disorders. A flavonoid complex called silymarin can be extracted from the seeds of milk thistle, and is believed to be the biologically active component. The terms "milk thistle" and "silymarin" are often used interchangeably.

Milk thistle products are popular in Europe and the United States for various types of liver disease. Although numerous human trials have been published, most studies have not been well designed or reported.

Selected combination products: (Iberogast, STW-5) containing extracts from bitter candy tuft, chamomile flower, peppermint leaves, caraway fruit, licorice root, lemon balm leaves, angelica root, celandine herbs, milk thistle fruit and its research preparation STW-5-S (without bitter candy tuft).

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidence

Chronic hepatitis (liver inflammation)

Several studies of oral milk thistle for hepatitis caused by viruses or alcohol report improvements in liver tests. However, most studies have been small and poorly designed. More research is needed before a recommendation can be made.

Cirrhosis

Multiple studies from Europe suggest benefits of oral milk thistle for cirrhosis. In experiments up to 5 years long, milk thistle has improved liver function and decreased the number of deaths that occur in cirrhotic patients. Although these results are promising, most studies have been poorly designed. Better research is necessary before a strong recommendation can be made.

Acute viral hepatitis

Research on milk thistle for acute viral hepatitis has not provided clear results, and milk thistle cannot be recommended for this potentially life-threatening condition.

Amanita phalloides mushroom poisoning

Milk thistle has been used traditionally to treat Amanita phalloides mushroom poisoning, and several animal studies and isolated human cases have suggested possible benefits. However, there are not enough reliable studies in humans to support this use of milk thistle.

Cancer prevention

There are early reports from laboratory experiments that the chemicals silymarin and silibinin in milk thistle reduce the growth of human breast, cervical, and prostate cancer cells. There is also one report of a patient with liver cancer who improved following treatment with milk thistle. However, this research is too early to draw firm conclusions, and effects have not been shown in high-quality human trials.

Diabetes (in patients with cirrhosis)

A small number of studies suggest possible improvements of blood sugar control in cirrhotic patients with diabetes. However, there is not enough scientific evidence to recommend milk thistle for this use.

High cholesterol

Although animal and laboratory research suggests cholesterol-lowering effects of milk thistle, human studies have provided unclear results. Further studies are necessary before a recommendation can be made.

Liver damage from drugs or toxins

Several studies suggest possible benefits of milk thistle to treat or prevent liver damage caused by drugs or toxic chemicals. Results of this research are not clear, and most studies have been poorly designed. Therefore, there is not enough scientific evidence to recommend milk thistle for this use.

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Acute liver injury, adult cancer, alcoholic cirrhosis, amiodarone toxicity reactions, antibacterial, anti-carcinogenic, anti-inflammatory, antiproliferative, antisclerotic, antiulcerous effect, asthma, bladder cancer, bleeding, breast cancer, bronchitis, cancer, chemopreventive, diabetic nerve pain, dietary supplement, dyspepsia, EGF-R expressing tumors, fatty liver, gallstones, hangover, hemorrhoids, hepatoprotector, hormone-refractory human prostate cancer, illness, immunomodulator, immunostimulant, internal protections, ischemic injury, liver "cleansing," liver cancer, liver damage, liver dysfunction, liver regeneration, loss of appetite, lung cancer, malaria, menstrual problems, peritoneal macrophages, plague, prostate cancer psoriasis, radiation toxicity, reparative ability, restorative influence, skin cancer, snakebites, spleen disorders, sunscreen surgery, UV irradiation-induced apoptosis, varicose veins, vital activity, work capacity.

Dosing

Standardization

Standardization involves measuring the amount of certain chemicals in products to try to make different preparations similar to each other. It is not always known if the chemicals being measured are the "active" ingredients. Milk thistle is often standardized to contain 70-80% silymarin. Silymarin is a mixture of three flavonolignans: silybin, silidianin, and silychristin. Despite standardization, different preparations and brands may have different effects in the body. Silipide® (IdB 1016) is a special milk thistle product that is designed to be absorbed better into the body. Doses of Silipide® are measured by "silybin equivalents."

One study analyzing stability of milk thistle tincture found a shelf life of approximately 3 months.

Adults (18 years and older)

Cirrhosis: Silymarin (Legalon®) 280mg-420mg per day divided into 2-3 doses. Up to 450mg daily divided into three doses has been studied.

Hepatitis (chronic): Silipide® (IdB 1016) 160-480mg per day in silybin equivalents, or silymarin (Legalon®) 420mg daily divided into three doses.

Hepatitis (acute, viral): Silymarin 420mg daily divided into three doses.

Drug/toxin-induced hepatotoxicity: Silymarin (Legalon®) 280-420mg daily divided into three doses. Up to 800mg daily has been studied.

High cholesterol: Silymarin 420mg per day has been studied.

Diabetes mellitus (insulin-dependent) associated with cirrhosis: Silymarin (Legalon®) 230-600mg per day has been studied. Effectiveness and safety have not been proven.

Children (younger than 18 years)

There is not enough scientific data to recommend milk thistle for use in children.

Tags: Herbal Medicine

About the Author

medlineplus.gov
MedlinePlus will direct you to information to help answer health questions. MedlinePlus brings together authoritative information from NLM, the National Institutes of Health (NIH), and other government agencies and health-related organizations. MedlinePlus also has extensive information about drugs, an illustrated medical encyclopedia, interactive patient tutorials, and latest health news.