2.2. | Study selection criteria
All titles and abstracts were screened to evaluate eligibility for inclusion. For a study to be included in the systematic review, it had to be a) RCTs with either parallel or cross‐over design, b) participants aged 18 years or older, c) intervention with berberies aristate/silybum marianum, d) assessment of liver enzymes. Exclusion criteria were; a) they were conducted on animals, pregnant women or children; also b) unpublished data, books, letters, comments, congress abstracts, reviews, meta-analyses and observational studies were excluded.