We have read the interesting article by Adler et al (Gut 2008;57:59–64) concerning the usefulness of narrow-band imaging (NBI) in the detection of colorectal adenoma. In their study, the authors showed that NBI significantly increased the number of polyps detected when compared with conventional white light colonoscopy. However, this difference was limited to those small hyperplastic polyps <10 mm. The result was not significant for adenoma. In addition, NBI can possibly induce a learning effect because the difference between NBI and conventional colonoscopy disappeared after …