Milk thistle may be beneficial in the treatment of hepatitis, liver disease, and ulcers, but duration of treatment varies. According to a study conducted by Dr. Peter Ferenci at the University of Vienna, daily dosages of milk thistle are safe for up to 41 months. Another study, published in the "Scandinavian Journal of Gastroenterology," indicated that silymarin can provide measurable health benefits after only four weeks.
According to Dr. Francine Ranione at Yeshiva University, "Clinical studies [on the effects of silymarin] are largely heterogeneous and contradictory." She points out that existing research has examined such a wide variety of conditions, dosages and treatment durations that the evidence for silymarin's effectiveness is "conflicting" and "limited" at best.
Even though milk thistle is a safe treatment ranging from one month to a few years, Dr. Rainone indicates that research does not agree on the most effective length of treatment. The most accurate way to decide how long to take milk thistle is to consult your health care professional.
Paul Riggins began writing professionally online in 2010. He is a certified technical writer and editor and a graduate of the University of Washington's Human-Centered Design and Engineering program. He currently focuses on technical writing and fiction.