Irritable bowel syndrome (IBS) is a quality of life impairing disorder of gut-brain interaction, which manifest itself as recurrent abdominal pain and disordered bowel habits in predisposed individuals who present with normal findings at standard clinical tests. Although the causes behind disturbed gut function and gut-brain interaction remain largely unknown, changes in gut microenvironment (e.g., gut microbiota alterations, intestinal barrier dysfunction, dysregulated immune response) seem to play a role. Recent studies suggest, despite the absence of systemic signs of classical allergy, nutritional components can trigger local allergy like immune responses which eventually lead to local edema formation, mast cell activation and increased hypersensitivity in IBS patients. Intriguingly, microbiota-diet interactions seem to play a role in breaking of oral tolerance to food antigens. In this study we aim to investigate clinical, immune and microbiome parameters relevant for local food allergy, through exploratory analysis of clinical data and biologic samples obtained from IBS patients with and without food induced symptoms.