Background: Irritable Bowel Syndrome (IBS) is a common functional Gastrointestinal disorder, characterized by recurrent abdominal pain or discomfort in association with change in stool form or stool frequency. These symptoms have a relapsing and remitting course. The pathophysiology of IBS is not yet well understood. A probiotic is a live organism that when ingested in enough amounts, causes a health benefit to the host. While probiotics have been used on an empiric basis to manage IBS symptoms, several recent researches provide a more logical basis for probiotics use in this field. Objectives: This study was performed to assess the effect of daily use of probiotic on IBS symptoms, pro-inflammatory cytokine (IL-8 level) and intestinal flora. Methodology: This study included total number of 90 patients complaining of IBS symptoms. These patients comprised 22 men and 68 women. They were divided into two groups: Group I included 45 patients complaining of IBS symptoms and treated with probiotics and group II included 45 patients complaining of IBS symptoms and treated with symptomatic treatment. All patients in the study were subjected to blood sampling for measurement of interleukin- 8 and stool sampling for stool culture. Patients of group1 were treated with probotic daily for 4 weeks (Lactobacillus delbruekii and Lactobacillus fermentum 10 billions twice daily). Results: There were statistical significance difference between Group I and Group II in abdominal pain improvement with increase number of improved cases among group1. Regarding improvement time it was statisticaly significant shorter in Group I comparing to group II. There was no statistical significance difference between Group I and Group II in base line IL-8 level. While there was statistical significance differences between them in its level after 1 month. Regarding comparison within the same group there was highly statistical significance differences between base line IL-8 levels and after 1 month results in group I. While there were statistical significance differences between Group I and Group II in IL-8 level after 1 month. There were no statistical significance difference between Group I and Group II regarding base line and after 1 month stool culture results. Regarding comparison within the same group there were highly statistical significance differences between base line stool culture results and after 1 month results in both groups with higher significance difference in group I . Conclusion: Probiotics are an effective treatment option for IBS patients. Daily use of probiotic will improve IBS symptoms, decrease IL-8 level and restore normal intestinal flora.