Inclusion criteria were patients aged 18 years or older who underwent a lactulose hydrogen-methane breath test to assess SIBO. Exclusion criteria were patients who 1) had taken antibiotics, H2 receptor antagonists, proton pump inhibitors, probiotics, or medications that affect gastrointestinal motility within the last month; 2) had undergone vagotomy; 3) had a history of gastrointestinal surgery; 4) had a colonoscopy, barium enema, or any other test with a bowel preparation within one week; 5) had postprandial hypoglycemia; 6) were diagnosed with irritable bowel syndrome, inflammatory bowel disease, or chronic pancreatitis.