Peppermint oil has shown to be effective in the treatment of Irritable Bowel Syndrome (IBS) symptoms in several meta-analyses. However, the level of evidence is moderate and peppermint oil remains relatively under-used in IBS. Therefore, the investigators will conduct a multicenter randomized, placebo controlled trial to investigate the effects of an eight-week peppermint oil treatment in IBS patients according to current European Medicines Agency (EMA) / US Food and Drug Administration (FDA) guidelines. To improve efficacy and to reduce side effects, the investigators aim to study the use of a new peppermint oil formulation, a colon-targeted-delivery capsule that will release the oil in the (ileo-) colonic region specifically.