Irritable bowel syndrome (IBS) is one of the most common chronic diseases of the gut-brain axis. The underlying pathophysiology is multifactorial, poorly understood and differs between the subtypes: constipation-dominant IBS, diarrhea-dominant IBS, mixed IBS, and unspecified IBS. Although it is considered a motility disorder, no uniform motility patterns have been found in IBS patients and no link has yet been found between the motility patterns and the typical complaints such as nausea, fullness, cramps and flatulence. These symptoms are often diagnosed after a meal and research has shown that especially fermentable oligo, di, monosaccharides and polyols (FODMAPs) give rise to symptoms. Many studies have tested the effect of these FODMAPs after oral administration, but little is known about their direct effect on the colon. In this double-blind cross-over study, 15 healthy volunteers are subjected to 3 colonoscopies in which a catheter is placed to measure the pressures in the large intestine and to administer the dissolved FODMAPs. Volunteers will follow a diet low in fiber and FODMAPs 3 days before each study visit. In addition, they will have to record their daily bowel movements during the week of their study visit and fill in 2 short questionnaires on the day of the study visit regarding their gastrointestinal complaints. There will be at least 2 weeks between the 3 study visits to avoid any overlap between the FODMAPs.