Gastrointestinal Transit: Passage of food (sometimes in the form of a test meal) through the gastrointestinal tract as measured in minutes or hours. The rate of passage through the intestine is an indicator of small bowel function.Gastric Emptying: The evacuation of food from the stomach into the duodenum.Gastrointestinal Motility: The motor activity of the GASTROINTESTINAL TRACT.Ileus: A condition caused by the lack of intestinal PERISTALSIS or INTESTINAL MOTILITY without any mechanical obstruction. This interference of the flow of INTESTINAL CONTENTS often leads to INTESTINAL OBSTRUCTION. Ileus may be classified into postoperative, inflammatory, metabolic, neurogenic, and drug-induced.Defecation: The normal process of elimination of fecal material from the RECTUM.Croton Oil: Viscous, nauseating oil obtained from the shrub Croton tiglium (Euphorbaceae). It is a vesicant and skin irritant used as pharmacologic standard for skin inflammation and allergy and causes skin cancer. It was formerly used as an emetic and cathartic with frequent mortality.Castor Oil: Oil obtained from seeds of Ricinus communis that is used as a cathartic and as a plasticizer.Digestive System Physiological Phenomena: Properties and processes of the DIGESTIVE SYSTEM as a whole or of any of its parts.Zanthoxylum: A plant genus of the family RUTACEAE. Some members of Zanthoxylum are reclassified from ELEUTHEROCOCCUS, Melicope, and EVODIA. The twigs are used as dental brushing sticks (TOOTHBRUSHING). Most plants that are called Fagara have been reclassified as Zanthoxylum, however some Fagara were reclassified to MELICOPE (also in the Rutacea family) or to GLEDITSIA (a genus in the FABACEAE family).Medicine, East Asian Traditional: Medical practice or discipline that is based on the knowledge, cultures, and beliefs of the people in EAST ASIA.Loperamide: One of the long-acting synthetic ANTIDIARRHEALS; it is not significantly absorbed from the gut, and has no effect on the adrenergic system or central nervous system, but may antagonize histamine and interfere with acetylcholine release locally.Constipation: Infrequent or difficult evacuation of FECES. These symptoms are associated with a variety of causes, including low DIETARY FIBER intake, emotional or nervous disturbances, systemic and structural disorders, drug-induced aggravation, and infections.Nalbuphine: A narcotic used as a pain medication. It appears to be an agonist at kappa opioid receptors and an antagonist or partial agonist at mu opioid receptors.Antidiarrheals: Miscellaneous agents found useful in the symptomatic treatment of diarrhea. They have no effect on the agent(s) that cause diarrhea, but merely alleviate the condition.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.ExplosionsMedetomidine: An agonist of RECEPTORS, ADRENERGIC ALPHA-2 that is used in veterinary medicine for its analgesic and sedative properties. It is the racemate of DEXMEDETOMIDINE.Colon: The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.Receptors, Serotonin, 5-HT4: A subtype of G-protein-coupled SEROTONIN receptors that preferentially couple to GS STIMULATORY G-PROTEINS resulting in increased intracellular CYCLIC AMP. Several isoforms of the receptor exist due to ALTERNATIVE SPLICING of its mRNA.Lantana: A plant genus of the family VERBENACEAE. Members contain lantadene and other TRITERPENES.Intestine, Small: The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.Gastrointestinal Tract: Generally refers to the digestive structures stretching from the MOUTH to ANUS, but does not include the accessory glandular organs (LIVER; BILIARY TRACT; PANCREAS).Ginger: Deciduous plant rich in volatile oil (OILS, VOLATILE). It is used as a flavoring agent and has many other uses both internally and topically.Pentazocine: The first mixed agonist-antagonist analgesic to be marketed. It is an agonist at the kappa and sigma opioid receptors and has a weak antagonist action at the mu receptor. (From AMA Drug Evaluations Annual, 1991, p97)Peristalsis: A movement, caused by sequential muscle contraction, that pushes the contents of the intestines or other tubular organs in one direction.Morphine: The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.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)Metoclopramide: A dopamine D2 antagonist that is used as an antiemetic.Intestinal Absorption: Uptake of substances through the lining of the INTESTINES.Analgesics, Opioid: Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.Yohimbine: A plant alkaloid with alpha-2-adrenergic blocking activity. Yohimbine has been used as a mydriatic and in the treatment of ERECTILE DYSFUNCTION.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Clonidine: An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION.Ileum: The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.Dietary Fiber: The remnants of plant cell walls that are resistant to digestion by the alimentary enzymes of man. It comprises various polysaccharides and lignins.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Digestive System: A group of organs stretching from the MOUTH to the ANUS, serving to breakdown foods, assimilate nutrients, and eliminate waste. In humans, the digestive system includes the GASTROINTESTINAL TRACT and the accessory glands (LIVER; BILIARY TRACT; PANCREAS).Delayed-Action Preparations: Dosage forms of a drug that act over a period of time by controlled-release processes or technology.Diarrhea: An increased liquidity or decreased consistency of FECES, such as running stool. Fecal consistency is related to the ratio of water-holding capacity of insoluble solids to total water, rather than the amount of water present. Diarrhea is not hyperdefecation or increased fecal weight.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.Intestines: The section of the alimentary canal from the STOMACH to the ANAL CANAL. It includes the LARGE INTESTINE and SMALL INTESTINE.Probiotics: Live microbial DIETARY SUPPLEMENTS which beneficially affect the host animal by improving its intestinal microbial balance. Antibiotics and other related compounds are not included in this definition. In humans, lactobacilli are commonly used as probiotics, either as single species or in mixed culture with other bacteria. Other genera that have been used are bifidobacteria and streptococci. (J. Nutr. 1995;125:1401-12)Biological Availability: The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action.Adrenergic alpha-Agonists: Drugs that selectively bind to and activate alpha adrenergic receptors.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Cross-Over Studies: Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)Muscle, Smooth: Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)Administration, Oral: The giving of drugs, chemicals, or other substances by mouth.Muscle Contraction: A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.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.