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.

Key to grades

A
Strong scientific evidence for this use
B
Good scientific evidence for this use
C
Unclear scientific evidence for this use
D
Fair scientific evidence against this use (it may not work)
F
Strong scientific evidence against this use (it likely does not work)

Grading rationale

Evidence gradeCondition to which grade level applies
B

Cirrhosis (liver scarring)

Multiple studies from Europe suggest benefits of oral milk thistle for cirrhosis. In studies up to five years long, milk thistle slightly improved liver function and decreased the number of deaths in people with liver disease. Although these results are promising, most studies have been poorly designed. Better research is necessary before a strong conclusion can be made.
B

Diabetes (type 2)

Research showed that milk thistle improved control of blood sugar in people with diabetes with and without liver disease. Higher quality research is necessary before strong conclusions can be made.
B

Diabetic nephropathy (kidney disease)

Research suggests that silymarin improves blood and urine markers associated with diabetic kidney disease. Further high quality research is needed before a conclusion can be made.
B

Liver disease (chronic)

Several studies of milk thistle in liver disease 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 conclusion can be made.
C

Acute viral hepatitis

Existing research shows unclear benefits for the use of milk thistle in acute viral hepatitis, or liver inflammation due to an infection from a virus. Further research is needed to draw conclusions.
C

Allergic nasal symptoms

Limited research showed that milk thistle reduced the severity of allergic nasal symptoms. Further study is needed to draw conclusions.
C

Amanita phalloides mushroom poisoning

Milk thistle has been used traditionally to treat Amanita phalloides mushroom poisoning. Strong research in humans supporting this use is lacking. Further research is necessary.
C

Antioxidant

Early research suggests that milk thistle, alone or given with vitamin E, improves antioxidant status. Although promising, further high quality research is needed before conclusions can be made.
C

Cancer

Early evidence reported unclear results for the use of milk thistle in combination with other supplements in people with cancer. One person reported an improvement in liver cancer after taking milk thistle. Further research is needed to draw conclusions.
C

Fertility

In women undergoing artificial fertilization (in vitro fertilization, IVF), silymarin used in combination with standard therapy has demonstrated mixed results. More research is needed to reach conclusions.
C

Heartburn

An herbal preparation containing milk thistle may be effective in decreasing heartburn. Research of milk thistle alone is necessary for conclusions to be drawn.
C

High cholesterol

Although non-human research suggests cholesterol-lowering effects of milk thistle, human studies have provided mixed results. Further studies are necessary before a firm conclusion can be made.
C

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 unclear, and most studies have been poorly designed. Higher quality trials are necessary to draw conclusions.
C

Menopause

An herbal preparation containing milk thistle may be effective in decreasing menopausal symptoms. Research of milk thistle alone is necessary for conclusions to be drawn.
C

Neurodegenerative disorders (disorders due to neuron destruction)

In early research, a preparation of milk thistle and other supplements has demonstrated a beneficial effect on people with various neurodegenerative disorders, including multiple sclerosis (MS), Parkinson's disease, and Alzheimer's disease. Further high-quality research with milk thistle alone is needed before any firm conclusions can be made.
C

Obsessive compulsive disorder

In human research, milk thistle reduced symptoms of obsessive compulsive disorder (OCD), but lacked benefits compared to regular treatment. Further research is needed to draw conclusions on the benefits of milk thistle in OCD patients.
C

Osteoarthritis

Early evidence suggests that milk thistle has anti-inflammatory effects in people with osteoarthritis. Further high quality research is needed before conclusions can be made.
C

Radiation skin irritation

Early research in breast cancer patients suggests that silymarin (Levidaerm®) helps ease radiotherapy-induced toxic skin reactions compared to standard care. Further high quality research is warranted.
F

Beta-thalassemia (genetic blood disorder)

Human research showed that adding milk thistle to regular therapy lacked further benefits for iron overload in people with beta-thalassemia. Further study is needed before firm conclusions may be made.

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.

Antibacterial, anti-inflammatory, asthma, bad breath, biliary colic (pain due to gallstones), bleeding, bronchitis (chronic cough), bubonic plague (fatal disease), central nervous system disorders, cleansing vital organs, clogged arteries, constipation, cough, depression, diabetic nerve damage, dialysis (kidney replacement therapy), eczema (inflammatory skin condition), gallbladder disease, gallstones, hemochromatosis (too much iron in body), hemorrhoids, high blood pressure associated with pregnancy, hyperthyroid (overactive thyroid gland), immune function, infection prevention, ischemic injury (injury due to lack of oxygen), jaundice (yellowing of the skin), lactation stimulant, malaria, menstrual disorders, peritonitis (inflammation of the abdomen wall), psoriasis (inflammatory skin condition), radiation sickness, recovery from surgery, snakebite, spleen disorders, swelling, toxic kidney damage, tumors, ulcers, ultraviolet light skin damage protection, uterine disorders, varicose veins (abnormal and painful veins), vasculitis (inflammation of blood vessels).

Portions of this document last updated: Nov. 01, 2013

This evidence-based monograph was prepared by The Natural Standard Research Collaboration

www.naturalstandard.com