Prospective, open label trial to establish the ability of the SIMBA Capsule to accurately obtain a sample from the small bowel of participants with IBS (10 constipation-predominant (IBS-C) and 10 diarrhea-predominant (IBS-D)) and healthy participants (n=10). The accuracy of targeting the small bowel will be established by visual confirmation via X-ray. The clinical utility of the collected sample will be evaluated by analysis with samples obtained by the current gold standard (duodenal aspirate), as well as stool analysis and LBT.

Inclusion Criteria

1. Aged between 18 and 70 years.
2. Diagnosis of IBS by Rome 4 criteria (IBS groups) or no previous diagnosis of IBS or suspected IBS (Control group).
3. Ability to understand and provide informed consent.
4. Ability and willingness to meet the required schedule and study interventions.
5. No planned change in diet or medical interventions during the study duration.
6. Adequate mobility to transfer repeatedly between X-ray (standing or lying), and waiting (sitting).
7. Willing and able to undergo a sedated esophagogastroduodenoscopy (EGD) with aspirate and brushing.

Exclusion Criteria

1. Prior gastrointestinal disease, surgery, or radiation treatment which, in the investigator's opinion, would lead to intestinal structuring or obstruction with a risk of capsule non-excretion (particular diseases which would be assessed on a case-by-case basis would include, achalasia, eosinophilic esophagitis, Crohn's disease, cancer diagnosis or treatment within the past year, or previous esophageal, gastric, small intestinal, or colonic surgery. Appendectomy or cholecystectomy more than 3 months prior to enrollment are acceptable).
2. Use of any medications in the previous week that could substantially alter gastrointestinal motor function (e.g., opioids, prokinetics, anticholinergics, laxatives), or acidity (PPI, H2RA).
3. History of oropharyngeal dysphagia or other swallowing disorder with a risk of aspiration of the capsule.
4. Females of childbearing age who are not practicing birth control and/or are pregnant or lactating.
5. No antibiotics, or colon cleanses/bowel prep for 2 weeks.
6. < 2 bowel movements per week (Control Group).