Dyspepsia: Impaired digestion, especially after eating.Helicobacter pylori: A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus CAMPYLOBACTER, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus HELICOBACTER. It has been officially transferred to Helicobacter gen. nov. (see Int J Syst Bacteriol 1989 Oct;39(4):297-405).Helicobacter Infections: Infections with organisms of the genus HELICOBACTER, particularly, in humans, HELICOBACTER PYLORI. The clinical manifestations are focused in the stomach, usually the gastric mucosa and antrum, and the upper duodenum. This infection plays a major role in the pathogenesis of type B gastritis and peptic ulcer disease.Peptic Ulcer: Ulcer that occurs in the regions of the GASTROINTESTINAL TRACT which come into contact with GASTRIC JUICE containing PEPSIN and GASTRIC ACID. It occurs when there are defects in the MUCOSA barrier. The common forms of peptic ulcers are associated with HELICOBACTER PYLORI and the consumption of nonsteroidal anti-inflammatory drugs (NSAIDS).Gastric Emptying: The evacuation of food from the stomach into the duodenum.Anti-Ulcer Agents: Various agents with different action mechanisms used to treat or ameliorate PEPTIC ULCER or irritation of the gastrointestinal tract. This has included ANTIBIOTICS to treat HELICOBACTER INFECTIONS; HISTAMINE H2 ANTAGONISTS to reduce GASTRIC ACID secretion; and ANTACIDS for symptomatic relief.Gastrointestinal Agents: Drugs used for their effects on the gastrointestinal system, as to control gastric acidity, regulate gastrointestinal motility and water flow, and improve digestion.Endoscopy, Gastrointestinal: Endoscopic examination, therapy or surgery of the gastrointestinal tract.Omeprazole: A 4-methoxy-3,5-dimethylpyridyl, 5-methoxybenzimidazole derivative of timoprazole that is used in the therapy of STOMACH ULCERS and ZOLLINGER-ELLISON SYNDROME. The drug inhibits an H(+)-K(+)-EXCHANGING ATPASE which is found in GASTRIC PARIETAL CELLS.Gastrointestinal Diseases: Diseases in any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM.Cisapride: A substituted benzamide used for its prokinetic properties. It is used in the management of gastroesophageal reflux disease, functional dyspepsia, and other disorders associated with impaired gastrointestinal motility. (Martindale The Extra Pharmacopoeia, 31st ed)Gastrointestinal Motility: The motor activity of the GASTROINTESTINAL TRACT.Antacids: Substances that counteract or neutralize acidity of the GASTROINTESTINAL TRACT.Gastroscopy: Endoscopic examination, therapy or surgery of the interior of the stomach.Aerophagy: Spasmodic swallowing of air.Stomach: An organ of digestion situated in the left upper quadrant of the abdomen between the termination of the ESOPHAGUS and the beginning of the DUODENUM.Gastritis: Inflammation of the GASTRIC MUCOSA, a lesion observed in a number of unrelated disorders.Colonic Diseases, Functional: Chronic or recurrent colonic disorders without an identifiable structural or biochemical explanation. The widely recognized IRRITABLE BOWEL SYNDROME falls into this category.Gastroesophageal Reflux: Retrograde flow of gastric juice (GASTRIC ACID) and/or duodenal contents (BILE ACIDS; PANCREATIC JUICE) into the distal ESOPHAGUS, commonly due to incompetence of the LOWER ESOPHAGEAL SPHINCTER.Duodenal Ulcer: A PEPTIC ULCER located in the DUODENUM.Bismuth: A metallic element that has the atomic symbol Bi, atomic number 83 and atomic weight 208.98.Clarithromycin: A semisynthetic macrolide antibiotic derived from ERYTHROMYCIN that is active against a variety of microorganisms. It can inhibit PROTEIN SYNTHESIS in BACTERIA by reversibly binding to the 50S ribosomal subunits. This inhibits the translocation of aminoacyl transfer-RNA and prevents peptide chain elongation.Irritable Bowel Syndrome: A disorder with chronic or recurrent colonic symptoms without a clearcut etiology. This condition is characterized by chronic or recurrent ABDOMINAL PAIN, bloating, MUCUS in FECES, and an erratic disturbance of DEFECATION.Abdominal Pain: Sensation of discomfort, distress, or agony in the abdominal region.Heartburn: Substernal pain or burning sensation, usually associated with regurgitation of gastric juice into the esophagus.Amoxicillin: A broad-spectrum semisynthetic antibiotic similar to AMPICILLIN except that its resistance to gastric acid permits higher serum levels with oral administration.Proton Pump Inhibitors: Compounds that inhibit H(+)-K(+)-EXCHANGING ATPASE. They are used as ANTI-ULCER AGENTS and sometimes in place of HISTAMINE H2 ANTAGONISTS for GASTROESOPHAGEAL REFLUX.Histamine H2 Antagonists: Drugs that selectively bind to but do not activate histamine H2 receptors, thereby blocking the actions of histamine. Their clinically most important action is the inhibition of acid secretion in the treatment of gastrointestinal ulcers. Smooth muscle may also be affected. Some drugs in this class have strong effects in the central nervous system, but these actions are not well understood.Pyloric Antrum: The region between the sharp indentation at the lower third of the STOMACH (incisura angularis) and the junction of the PYLORUS with the DUODENUM. Pyloric antral glands contain mucus-secreting cells and gastrin-secreting endocrine cells (G CELLS).Metronidazole: A nitroimidazole used to treat AMEBIASIS; VAGINITIS; TRICHOMONAS INFECTIONS; GIARDIASIS; ANAEROBIC BACTERIA; and TREPONEMAL INFECTIONS. It has also been proposed as a radiation sensitizer for hypoxic cells. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985, p133), this substance may reasonably be anticipated to be a carcinogen (Merck, 11th ed).Gastroparesis: Chronic delayed gastric emptying. Gastroparesis may be caused by motor dysfunction or paralysis of STOMACH muscles or may be associated with other systemic diseases such as DIABETES MELLITUS.Benzyl CompoundsEructation: The ejection of gas or air through the mouth from the stomach.Bile Reflux: Retrograde bile flow. Reflux of bile can be from the duodenum to the stomach (DUODENOGASTRIC REFLUX); to the esophagus (GASTROESOPHAGEAL REFLUX); or to the PANCREAS.Stomach Diseases: Pathological processes involving the STOMACH.Breath Tests: Any tests done on exhaled air.Duodenitis: Inflammation of the DUODENUM section of the small intestine (INTESTINE, SMALL). Erosive duodenitis may cause bleeding in the UPPER GI TRACT and PEPTIC ULCER.Postprandial Period: The time frame after a meal or FOOD INTAKE.Simethicone: A poly(dimethylsiloxane) which is a polymer of 200-350 units of dimethylsiloxane, along with added silica gel. It is used as an antiflatulent, surfactant, and ointment base.Esophagitis: INFLAMMATION, acute or chronic, of the ESOPHAGUS caused by BACTERIA, chemicals, or TRAUMA.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Stomach Ulcer: Ulceration of the GASTRIC MUCOSA due to contact with GASTRIC JUICE. It is often associated with HELICOBACTER PYLORI infection or consumption of nonsteroidal anti-inflammatory drugs (NSAIDS).Ranitidine: A non-imidazole blocker of those histamine receptors that mediate gastric secretion (H2 receptors). It is used to treat gastrointestinal ulcers.Flatulence: Production or presence of gas in the gastrointestinal tract which may be expelled through the anus.Duodenum: The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.Gastroenterology: A subspecialty of internal medicine concerned with the study of the physiology and diseases of the digestive system and related structures (esophagus, liver, gallbladder, and pancreas).Cholecystography: Radiography of the gallbladder after ingestion of a contrast medium.Gastric Mucosa: Lining of the STOMACH, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. The surface cells produce MUCUS that protects the stomach from attack by digestive acid and enzymes. When the epithelium invaginates into the LAMINA PROPRIA at various region of the stomach (CARDIA; GASTRIC FUNDUS; and PYLORUS), different tubular gastric glands are formed. These glands consist of cells that secrete mucus, enzymes, HYDROCHLORIC ACID, or hormones.Satiation: Full gratification of a need or desire followed by a state of relative insensitivity to that particular need or desire.Diagnostic Techniques, Digestive System: Methods and procedures for the diagnosis of diseases or dysfunction of the digestive system or its organs or demonstration of their physiological processes.Drug Therapy, Combination: Therapy with two or more separate preparations given for a combined effect.2-Pyridinylmethylsulfinylbenzimidazoles: Compounds that contain benzimidazole joined to a 2-methylpyridine via a sulfoxide linkage. Several of the compounds in this class are ANTI-ULCER AGENTS that act by inhibiting the POTASSIUM HYDROGEN ATPASE found in the PROTON PUMP of GASTRIC PARIETAL CELLS.