To investigate the prevalence of small intestinal bacterial overgrowth (SIBO) in patients with
colorectal cancer (CRC) after surgical treatment and observe whether gastrointestinal symptoms may improve with
rifaximin, 43 postoperative CRC patients (CRC group) and 30 healthy individuals (normal group) were subjected to the
glucose hydrogen breath test (GHBT). All the patients were asked to evaluate the gastrointestinal symptoms using the visual analogue scale (VAS). SIBO-positive patients were administered
rifaximin for 10 days on the basis of the original treatment. After the treatment, the patients were asked to undergo GHBT and re-evaluate the gastrointestinal symptoms score (GISS). The results demonstrated that 18 of the 43 postoperative patients with CRC were SIBO-positive (41.86%), which was significantly higher compared with the incidence in normal controls (6.67%) (P<0.05). GISS was higher in SIBO-positive patients (P<0.05). Following
rifaximin treatment, 6 of the 18 (33.33%) SIBO-positive patients had improved, as evaluated by GHBT and VAS. Additionally, the GISS in the SIBO-turned-negative group had improved significantly compared with that in the non-turned-negative group (P<0.05). The symptoms of all 18 SIBO-positive patients following
rifaximin treatment improved notably, particularly
diarrhea (P<0.05). In conclusion, postoperative CRC patients are more likely to develop SIBO compared with healthy individuals, and SIBO may aggravate digestive symptoms. The administration of
rifaximin improved the overall gastrointestinal symptoms, particularly
diarrhea, in SIBO-positive patients.