Gastroenterology nurses and associates will find it helpful to be informed about milk thistle (silybum marianum), a popular, safe and promising herb used by patients with liver disease. Silymarin is a derivative from the milk thistle plant with few side effects that has been safely used for centuries to treat liver ailments. Since the 1970s, there has been a reemergence of the marketing and use of silymarin. Research results of some small studies suggest silymarin has hepatoprotective, antiinflammatory, and regenerative properties producing a beneficial effect for some types of hepatitis. It is unclear, however, whether silymarin might interfere with the effect of interferon or ribavirin. A well-designed, placebo-controlled study of a larger population is needed. It is certainly encouraging that a large collaborative study is currently underway for milk thistle therapy in hepatitis C. This study is funded by NCCAM, the National Institute of Allergy and Infectious Diseases (NIAID), and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Research updates are available online at www.nccam.nih.gov and through the NCCAM Clearinghouse at 1-888-644-6226.