Milk thistle
Milk thistles are thistles of the genus Silybum Adans., flowering plants of the daisy family (Asteraceae). They are native to the Mediterranean regions of Europe, North Africa and the Middle East. Whilst health uses mostly for chronic liver disease have been traditionally claimed for the plant, increasing research is being undertaken on this and other possible medical uses.

# Description and classification
Members of this genus grow as annual or biennial plants. The erect stem is tall, branched  and furrowed but not spiny. The large, alternate leaves are waxy-lobed, toothed and thorny, as in other genera of thistle. The lower leaves are cauline (attached to the stem without petiole). The upper leaves have a clasping base. They have large, disc-shaped pink-to-purple, rarely white,  solitary flower heads at the end of the stem. The flowers consist of tubular florets. The phyllaries under the flowers occur in many rows, with the outer row with spine-tipped lobes and apical spines. The fruit is a black achene with a white pappus.
Only two species are currently classified in this genus:
- Silybum eburneum Coss. &  Dur., known as the Silver Milk Thistle, Elephant Thistle, or Ivory Thistle
Silybum eburneum Coss. &  Dur. var. hispanicum
- Silybum eburneum Coss. &  Dur. var. hispanicum
- Silybum marianum (L.) Gaertner, the Blessed Milk Thistle, which has a large number of other common names, such as Variegated Thistle.
The two species hybridise naturally, the hybrid being known as Silybum  gonzaloi Canto , Sanchez Mata  &  Rivas Mart. (S. eburneum var. hispanicum x S. marianum)
A number of other plants have been classified in this genus in the past but have since been relocated elsewhere in the light of additional research.
S. marianum is by far the more widely known species. It is believed to give some remedy for liver diseases (e.g. viral hepatitis) and an extract, silymarin, is used in medicine. The adverse effect of the medicinal use of milk thistle is loose stools.

# Health benefits
Milk thistles have been reported to have protective effects on the liver and to improve its function. They are typically used to treat liver cirrhosis, chronic hepatitis (liver inflammation), and gallbladder disorders. The active compound in Milk thistle credited with this effect is "silymarin", and is typically administered in amount ranging from 200-500mg per day (common Milk Thistle supplements have an 80% standardized extract of silymarin). Increasing research is being carried out into its possible medical uses and the mechanisms of such effects..  However, a previous literature review using only studies with both double-blind and placebo protocols concluded that milk thistle and its derivatives "does not seem to significantly influence the course of patients with alcoholic and/or hepatitis B or C liver diseases."
Treatment claims also include:
- Lowering cholesterol levels
- Reducing insulin resistance in people with type 2 diabetes who also have cirrhosis
- Reducing the growth of cancer cells in breast, cervical, and prostate cancers.
- Milk thistle is also used in many products claiming to reduce the effects of a hangover.
- Milk thistle can also be found as an ingredient in some energy drinks like the AriZona Beverage Company Green Tea energy drink and Rockstar Energy Drink.