• To determine the correlation between the orocecal transit time as measured by the SmartPill GI Monitoring System and the lactulose hydrogen breath test in both healthy subjects and patients with and without small bowel bacterial overgrowth. [ Time Frame: 5 Weeks ] [ Designated as safety issue: No ]
• To characterize pressure patterns as determined by SmartPill GI Monitoring System within the small bowel in healthy subjects and patients with and without small bowel bacterial overgrowth. [ Time Frame: 5 Weeks ] [ Designated as safety issue: No ]
• To determine whether the pH and pressure patterns within the stomach and small intestine as determined by SmartPill GI Monitoring System can discriminate between healthy human subjects and patients with small bowel bacterial overgrowth. [ Time Frame: 5 Weeks ] [ Designated as safety issue: No ]

The primary purpose of this exploratory study is to measure orocecal transit time using the SmartPill ambulant capsule technology and to compare this with the lactulose hydrogen breath test. Additionally, the ability of the SmartPill GI Monitoring System to discriminate between healthy human subjects and patients with small bowel bacterial overgrowth will be explored using analyses of both pH and pressure patterns within the stomach and small intestine. The study will be performed in both normal subjects and patients with and without small bowel bacterial overgrowth.

Small bowel bacterial overgrowth (SBBO), an increasingly recognized malabsorptive condition caused by the excessive growth of bacteria in the small bowel, results in a spectrum of symptoms such as diarrhea, bloating abdominal discomfort and weight loss. Multiple factors both internal and external to the individual prevent excessive small bowel bacterial colonization and determine the types of bacteria present. The most important factors within the individual are normal small bowel motility, which prevents attachment of ingested organisms, and gastric acid, which destroys many organisms before they reach the small intestine. The determination of small bowel motility is problematic due to limitations of the tests available (e.g., hydrogen breath test, scintigraphy and manometry).

The SmartPill capsule is a recently developed novel device that, following its ingestion, can measure pH, pressure and temperature as it moves through the gastrointestinal tract. These recordings can be used to measure gastrointestinal transit and, potentially, other aspects of gastrointestinal motility/function. Previous studies using this device have demonstrated the ability of the SmartPill to measure the gastric residence time using the duration of acidic pH recording with good correlation between the gastric residence time of the SmartPill capsule and conventional gastric emptying scintigraphy.

• Small Bowel Bacterial Overgrowth
• Gastrointestinal Diseases
• Stomach Diseases
• Digestive System Diseases

• No Intervention: Healthy Volunteers
• Other: 5 SBBO positive patients, 5 SBBO negative patients

Inclusion Criteria for Healthy Subjects:

1. Mentally competent and able to give informed consent.
2. Healthy males and females between 18-70 years of age with no current or previous chronic gastrointestinal symptoms.

Inclusion Criteria for Symptomatic Subjects:

1. Males and females between 18-70 years of age with symptoms suggestive of small bowel bacterial overgrowth (e.g., diarrhea, bloating, abdominal discomfort) for at least 3 months during the previous 12 months (need not be consecutive) who recently underwent an evaluation for small bowel bacterial overgrowth by either hydrogen breath testing or culture of small bowel aspirate at MCS.
2. Ability to stop laxatives and prokinetic and narcotic analgesic agents 3 days prior to the study and during the study period.
3. Ability to stop proton pump inhibitors 7 days prior to the study and H2RAs for 3 days prior to the study and during the study period.

Exclusion Criteria:

1. Subjects who are unable or unwilling to give informed consent or return for all required study visits.
2. Prior gastrointestinal surgery which has altered the anatomy of the esophagus, stomach or small/large intestine (exceptions include appendectomy, cholecystectomy and fundoplication).
3. Hypersensitivity to rifaximin.
4. Use of any medications in the previous week that could alter gastrointestinal motor function.
5. BMI > 38.
6. Previous history of bezoars.
7. Any abdominal surgery within the past 3 months.
8. Known or history of inflammatory bowel disease.
9. History of diverticulitis, diverticular stricture, and other intestinal strictures.
10. Tobacco use within eight hours prior to capsule ingestion and during the initial 8 hour recording on the first day.
11. Alcohol use within eight hours prior to capsule ingestion and throughout the entire monitoring period (up to 5 days).
12. Females of childbearing age who are not practicing birth control and/or are pregnant or lactating (A urine pregnancy test will be performed on female subjects prior to capsule ingestion).
13. Cardiovascular, endocrine, renal or other chronic disease likely to affect motility.
14. Use of medical devices such as pacemakers, infusion pumps, or insulin pumps.