Bull thistle, cardo blanco, Cardui mariae fructus, Cardui mariae herba, Cardum marianum L., Carduus marianus L., Chardon-Marie, emetic root, flavonolignans, Frauendistel, Fructus Silybi mariae, fruit de chardon Marie, heal thistle, holy thistle, isosilibinin, isosilybin, kanger, kocakavkas, kuub, lady's thistle, Legalon®, Marian thistle, mariana mariana, Mariendistel, Marienkrörner, Mary thistle, mild thistle, milk ipecac, natursil, natursilum, Our Lady's thistle, pig leaves, royal thistle, shui fei ji, silidianin, Silybi mariae fructus, silybin, silybinin, Silybum marianum, silychristin, silymarin, snake milk, sow thistle, St. Mary's thistle, thisylin, Venue thistle, variegated thistle, wild artichoke.
Milk thistle has been used medicinally for over 2,000 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.
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 strong recommendation can be made.
Multiple studies from Europe suggest benefits of oral milk thistle for cirrhosis. In experiments up to five 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 treatAmanita phalloidesmushroom poisoning. However, there are not enough reliable studies in humans to support this use of milk thistle.
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 a firm conclusion, 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.
Although animal and laboratory research suggests cholesterol-lowering effects of milk thistle, human studies have provided unclear results. Further studies are necessary before a firm 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.
Silymarin (Legalon®) 230-600 milligrams per day divided into two to three doses has been studied.
Silipide® (IdB 1016) 160-480 milligrams per day in silybin equivalents has also been studied.
There is not enough scientific data to recommend milk thistle for use in children.
People with allergies to plants in the aster family (Compositae, Asteraceae) or to daisies, artichokes, common thistle, kiwi, or to any of milk thistle's constituents (silibinin, silychistin, silydianin, silymonin, siliandrin) may have allergic reactions to milk thistle. Anaphylactic shock (a severe allergic reaction) from milk thistle tea or tablets has been reported in several patients. Overall, silymarin has a good safety record with rare case reports of gastrointestinal disturbances and allergic skin rashes published.
Milk thistle appears to be well tolerated in recommended doses for up to six years. Some patients in studies have experienced stomach upset, headache, and itching. There are rare reports of appetite loss, gas, heartburn, diarrhea, joint pain, and impotence with milk thistle use. One person experienced sweating, nausea, stomach pain, diarrhea, vomiting, weakness, and collapse after taking milk thistle. This reaction may have been due to an allergic reaction, and improved after 24 hours. High liver enzyme levels in one person taking milk thistle returned to normal after the person stopped taking the herb.
In theory, milk thistle may lower blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugars. Serum glucose levels may need to be monitored by a healthcare provider, and medication adjustments may be necessary.
Theoretically, because milk thistle plant extract might have estrogenic effects, women with hormone sensitive conditions should avoid milk thistle above ground parts. Some of these conditions include breast, uterine, and ovarian cancer, endometriosis, and uterine fibroids. The more commonly used milk thistle seed extracts are not known to have estrogenic effects.
Exacerbation of hemochromatosis has been associated with ingestion of milk thistle.
Milk thistle has been used historically to improve breast milk flow, and two brief studies of milk thistle in pregnant women reported no side effects. However, there is not enough scientific evidence to support the safe use of milk thistle during pregnancy or breastfeeding at this time.