Berberine treatment after colon polyp removal showed lasting protection against recurrence. Digest
People who have had colon polyps removed remain at risk of new growths, and preventive drugs either cause side effects or lack long-term evidence. Researchers in China revisited a randomized controlled trial of the compound berberine to test whether a two-year course could provide durable protection.
The original CBAR trial, which tested whether berberine could prevent the return of adenomas (a non-cancerous growth that can develop into cancer) in the colon or rectum, enrolled adults who had undergone endoscopic removal of these lesions and randomly assigned them to berberine tablets (0.3 grams twice daily) or a matching placebo for two years. In the new follow-up analysis, 648 of the 895 people who completed the trial later had at least one surveillance colonoscopy over a median of six years.
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Here's what the researchers observed:
- Participants who had taken berberine experienced a 42% lower risk of adenoma recurrence over the follow-up period. By the end of follow-up, about 35% of them had a recurrence compared with about 52% in the placebo group.
- When all types of abnormal growths (adenomas, serrated lesions, inflammatory polyps, and cancer) were considered together, berberine was linked to a 25% lower risk over time, and by the end of follow-up, about 63% of the berberine group had at least one such growth compared with 71% in the placebo group. However, this finding was less certain in additional analyses.
- This pattern is consistent with the observation that more serious adenomas and colorectal cancer remained rare in both groups and did not differ substantially. The clearest benefit appeared in small, lower-grade adenomas, which were about 44% less likely to develop over the follow-up period in those who had taken berberine.
These clinical patterns mirror experimental work in which berberine modifies gut microbial communities and the tumor microenvironment, dampening bacteria and pathways that favor tumor formation and improving metabolic disturbances. Although the study did not collect microbiome or mechanistic measurements, durable shifts in gut bacteria after a finite berberine course could underlie the sustained protection, while evidence for preventing advanced lesions or cancer remains limited.
Future studies could test different dosing schedules, include more diverse populations and directly track microbiome, metabolic, and genetic markers to clarify how berberine works and who benefits most. If replicated, a low-cost berberine regimen combined with quality colonoscopy surveillance could become a practical strategy to reduce long-term colorectal cancer risk. You can learn more about berberine in our detailed topic article.