If you had an adenoma polyp removed during a colonoscopy for colon cancer screening, you may already know that these polyps can come back and that they can become colon cancer. You were probably told to return for another colonoscopy in a few years, because up to 30% of adenomatous polyps come back. About 5% turn out to be cancer.

A new study from China has found that a traditional Chinese herbal medicine called berberine may significantly reduce the risk of regrowing these polyps, and reduce the risk of colon cancer.

The study was done in seven hospital centers across China. It included about 1,000 patients. All these patients had adenomatous polyps removed during a screening colonoscopy. About half the patients were randomly assigned to take berberine twice per day and the other half were given a placebo. After two years, there was a significant difference in polyp regrowth found during colonoscopies: 155 patients had new growths in the treatment group, compared with 216 in the placebo group. The study was reported in The Lancet.

In China, berberine is extracted from the herb coptis chinensis and has been used in Chinese medicine for centuries to treat diarrhea and stomach bugs. In animal research, mice treated with berberine had reduced colon tumor formation. The researchers say that the results of their study are promising because berberine is inexpensive and safe, but more studies will be needed to confirm their findings. In fact, a new study has already started.

Berberine is also found in many herbal products outside of China, including barberry, goldenseal, goldthread, Oregon grape and tree turmeric. It is most commonly used to treat diabetes, high cholesterol and high blood pressure. Berberine is considered safe in normal doses. In the Lancet study, the only side effect was constipation, which occurred very rarely. The study used a dose of 0.3 grams twice per day.

Berberine is not recommended during pregnancy or breastfeeding and it may interfere with some medications. As with any herbal supplement, you should check with your doctor first before trying it on your own.

Source: Study titled “Berberine versus placebo for the prevention of colorectal adenoma: a multicenter, double-blind, randomized controlled study,” by researchers at Shanghai Jiao Tong University School of Medicine, Shanghai, China, published in The Lancet.