provide a script discussing the CONS. Background and Aim Diet is a major contributor to irritable bowel syndrome (IBS) and is also a powerful tool for treatment of IBS. This study compared two diets and explored the effectiveness of the diets when combined with a probiotic for treatment of IBSD patients. Methods Phase I, patients were randomized into groups; control, cold/spicy/fried restricted diet (CSF res diet), IgG positive restricted diet (IgG res diet), and a combination both diets (CSF + IgG res diet). Phase II, patients were randomized into IgG res diet + placebo and IgG res diet + probiotic. Both interventions were 12 weeks in duration. Symptom Severity Scale (IBSDSSS) and IgG titer were assessed at the beginning and the end of the study. Results Totals of 214 and 167 patients completed the two parts of the study, respectively. After intervention, IBSDSSS and TIgG grade were significantly improved compared to baseline, with results similar to the control group. In general, there were decreases in IBSDSSS and TIgG grade that were significantly different among the groups. There were exceptions; no differences were observed for IBSDSSS between the IgG res diet and CSF + IgG res diet, or TIgG grade between