Not possible to include patients.

The hypothesis of the study is that the motility of the small intestine and the colon will alter according to the subtype of the irritable bowel syndrome (IBS) patient.

IBS is currently classified into following subtypes:

• Diarrhoea-IBS (IBS-D)
• Constipation-IBS (IBS-C)
• Mixed-IBS (IBS-M)
• Unsubtyped-IBS (IBS-U)

according to the Bristol scale.

Magnetic Tracking System (MTS) is a new minimal invasive technic that allows motility studies of the whole human gastrointestinal tract.

The magnetic cylindrical pill (6x15mm) is swallowed at 9 AM on day one. The recording is made until 4 PM and again from 8 AM until 2 PM on day two. The patient is placed in a bed and will be supplied with standardized food and fluid.

The Magnetic Tracking System consists of a 4 x 4 matrix of sensors positioned with respect to the anatomical reference points. Before measurements, the matrix is calibrated by offsetting the earth's and environmental magnetic fields. During the experiment, the magnet coordinates are continuously monitored and transmitted to a computer for processing and storage. Respiratory artifacts will be filtered out. Digestive movements will then be classified as 1) non-propulsive or 2) propulsive and transformed into either trajectory or dynamic graphs of the digestive motility.

The Magnetic Tracking System has the advantage from both radiographic and scintigraphic methods of conducting the tests without any radiation exposure to the patient. Preliminary studies have shown good concordance between the transit measured with the magnet and radiographic transit times.

The investigators wish to use this method, MTS, to compare the motility of the small intestine and the colon in patients with IBS-D and IBS-C as well as to compare these to groups to MTS done on healthy volunteers under the same conditions as the IBS patients.

A MTS study on healthy volunteers is all ready done under the same conditions as described abow in Denmark. This study has projectID 20080037 and is approved by the Danish Dataprotection Agency as well as The Regional Committee on Biomedical Research Ethics.

Inclusion Criteria:

• Patients aged over 18.
• Patients who are diagnosed with IBS according to the Rome III criteria.
• A total symptom score in GSRS-IBS at a minimum of 40 points.
• Patients who are psychologically stable and suitable for observation and able to provide informed consent.

Exclusion Criteria:

• Overt bowel diseases including inflammatory bowel disease.
• Pregnant or breast feeding.
• Patients who are considered unable to follow the planned programme of the study, including mental illness or physiological instability.
• Patients who are on medication with known influence on gastrointestinal motility including those for thyroid disease, diabetes mellitus, celiac disease and neurological disease.

12 patients with IBS-D and 12 patients with IBS-C who all meet the inclusion criteria.