• Department of Gastroenterology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
• Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
• Department of Pathology, Northwestern University, Chicago, Illinois.
• Department of Pharmacology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
• Department of Clinical Laboratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
• Division of Cancer Prevention, NCI, Bethesda, Maryland.
• Robert H. Lurie Cancer Center, Northwestern University, Chicago, Illinois.
• Department of Surgery and Northwestern University, Chicago, Illinois.
• Department of Preventive Medicine, Northwestern University, Chicago, Illinois.
• Division of Hematology and Medical Oncology, Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon. kaicwu@fmmu.edu.cn bergan@ohsu.edu.

The Chinese natural product, berberine, has biological properties that support its potential efficacy as a colon cancer prevention agent. Its longstanding use in China to treat gastrointestinal tract and rheumatologic disorders is generally regarded as safe, supporting initial investigations in an at-risk population, such as individuals with ulcerative colitis. However, the safety of berberine in this population is not established. Individuals living in China with biopsy-proven ulcerative colitis, ≤grade 2 dysplasia, and with a ulcerative colitis disease activity index (UCDAI) score ≤1 on mesalamine, were randomized 3:1 in a double-blind phase I trial to berberine 900 mg/day or placebo for 3 months, with the primary objective of assessing safety. Blood samples and biopsies of the colorectum, from prespecified locations, were collected prior to and following therapy. Secondary endpoints included changes in UCDAI score, and in tissue and plasma markers of inflammation. Of toxicities at least possibly related, one episode of grade 3 elevation in transaminases and one episode of grade 1 nausea were observed among 12 individuals on berberine, and none were observed among 4 on placebo. The mean plasma berberine concentration was 3.5 nmol/L after berberine treatment, significantly higher than 0.5 nmol/L with placebo. Berberine significantly decreased the Geboes grade in colonic tissue, but had a nonsignificant effect on other tissue or blood biomarkers related to cell growth and inflammation. The combination of berberine and mesalamine is well tolerated in Chinese with ulcerative colitis and may enhance mesalamine's anti-inflammatory effects in colonic tissue.