This study aimed to evaluate the effects of a Low-FODMAP diet on intestinal permeability, symptom severity, and quality of life in patients with Irritable Bowel Syndrome (IBS). Twenty-four patients diagnosed with IBS according to the Rome IV criteria were randomized to either a Low-FODMAP diet or a traditional diet for four weeks. Stool zonulin family peptides (ZFP), IBS Symptom Severity Score (IBS-SSS), and IBS Quality of Life (IBS-QOL) questionnaires were recorded at baseline and after the dietary intervention. In the Low-FODMAP group, FODMAP-containing foods were gradually reintroduced under dietitian supervision, and assessments were repeated at week 16 to evaluate long-term effects.