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Tradition

WARNING: DISCLAIMER: The below uses are based on tradition, scientific theories, or limited research. 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. There may be other proposed uses that are not listed below.

Dosing

Adults (18 years and older)

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.

Children (younger than 18 years)

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

Safety

DISCLAIMER: Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.

Allergies

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.

Side Effects and Warnings

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.

Pregnancy and Breastfeeding

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.