This study designed for detection the prevalence of IBS and efficacy of different drugs in treatment of these cases. The total patients that examined were 640. Out of 160 confirmed patients with IBS, sixty persons at different ages from 21-45 years and both sexes were selected and divided into 4 groups each group contain 15 persons: The research is a cross-sectional analysis of a population sample of people visiting hospitals and health centers in Baghdad, Iraq. Patients were not eligible if they had a prior experience of a gastrointestinal illness other than IBS or if they had undergone gastrointestinal surgery. G1 control negative, G2 Patients were given mebeverine pills having 135 milligrams three times weekly for 8 weeks, G3 patients were given 3-6 × 109 CFU per capsule, in equal representation of each probiotic were treated for 8 weeks, G4 patients were given tablet with a fine powder blend of three herbs: Mentha longifolia leaves (150 mg), Cyperus rotundus tubers (150 mg), and Zingiber officinale tubers (150 mg) (150 mg). For 8 weeks, the pills were given thrice weekly, once before each dinner and once an hour after eating. The current study showed that the age group 21-30 were highly infected when compared with another age groups. The results of treatment trails exhibited that mebeverine and herbs were most effected treatment as compared with probiotic treated group. The results of treatment trails exhibited that mebeverine and herbs were most effected treatment as compared with probiotic treated group Inconclusion, the prevalence of IBS was occurred mostly in female at age 21-30 and the most effective treatment were mebeverine and herbal combination.