The gut-brain-microbiota axis connects the nervous system with the metabolic, hormonal and immune functions of the intestines. Irritable bowel syndrome (IBS) is a functional gut disorder that commonly presents with psychological co-morbidities, and while animal studies show strong associations between stress and gut microbiota, studies in humans are rare. This review assesses the current literature on intestinal microbiome and its association with stress, anxiety and depression in patients with IBS. Based on existing studies, the authors found the gut microbiota forms a crucial link between the intestine and nervous system. Therapies targeted at both modulating the gut microbiome and psychological interventions are recommended. The authors conclude further randomised clinical trials are needed to better understand which therapies work best for patients with IBS.