An Easy-to-Understand Glossary of Common Digestive Health Terms

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Good bacteria, bad bacteria, gut microbiome, probiotics—as you know, we’re living in an era in which digestive health has become all the talk among health professionals. It’s no wonder: Mounting research demonstrates that our intestinal well-being impacts nearly every domain of our health, including immunity, mood, longevity and weight.

Word Cloud with Digestive Health Terms in Various Fonts and Colors on White Background } within all this talk there’s a ton of jargon that can leave even the most health-minded stumped. With this in mind, we’ve compiled the most often-used words and phrases in the realm of digestion and provided you with succinct definitions of each. Knowledge is power after all—and what could be more empowering than being proactive about your health? Let’s get started.

Your Digestive System Definition List


…refers to the process your body undergoes as it breaks down food that can be used for everything from growth to energy. Starting in the mouth, and traveling the length of the gastrointestinal tract, it involves a series of muscles and interactions—as well as cells and hormones—to coordinate the movement of food and its conversion into nutrients.


…is that roughly 8-inch muscular tube that runs from your throat, through your diaphragm, and into your stomach. Used when eating (as well as breathing and burping), it keeps food and secretions “from going down the windpipe,” Matthew Hoffman, MD, reports.

Acid reflux

…is a prevalent condition in which stomach acid flows back up into the esophagus. Characterized by a burning sensation in the chest area and/or throat, it’s also called acid indigestion and pyrosis.


…stands for gastroesophageal reflux disease—acid reflux that occurs more than twice a week.

Irritable bowel syndrome

…is another common digestive disorder (also known as IBS) that impacts the large intestine. While its causes are not entirely understood by experts, a number of factors play a role in its development. These include muscle contractions, your nervous system, inflammation, severe infections and “changes in bacteria in the gut (microflora),” the Mayo Clinic reports. Symptoms can range from mild to severe, and often include cramping, abdominal pain, bloating, gas, constipation and diarrhea.


…is another synonym for acid reflex. Alcohol, pregnancy, certain foods, and medications can all trigger heartburn—and exacerbate it.


…serves as the general term for a group of conditions that inflame the lining of the stomach. With symptoms ranging from vomiting and nausea to a gnawing abdominal pain, gastritis can be both acute (short-lived) or chronic. As the Mayo Clinic says, gastritis can “lead to ulcers and an increased risk of stomach cancer.”


…relates to the stomach and the intestines, and is often referred to as G.I. The gastrointestinal tract, meanwhile, is the organs “that food and liquids travel through when they are swallowed, digested, absorbed and leave the body as feces,” the NIH reports. These include the mouth, throat, esophagus, stomach, small intestine, large intestine, rectum and anus. As part of the digestive system, it’s also called the alimentary tract.


…is a class of enzymes that converts starch and glycogen into simple sugars. Present in saliva, and produced in the pancreas and salivary glands, it, too, plays a role in digestion.


…is a dark green or yellowish fluid, produced by the liver, that aids in digestion and the absorption of fats. It’s also liable for eliminating certain waste products from the body, such as excess cholesterol and hemoglobin from destroyed red blood cells.


…stands for deglycyrrhizinated licorice, which is often recommended for acid reflux. Shown to promote mucus activity, it may help cultivate a barrier to acid in the stomach and esophagus—and, thus, encourage tissue repair.

Digestive enzymes

…indicates compounds that assist the body in breaking food down into nutrients. Naturally occurring in the body, they’re produced primarily in the pancreas (as well as in the mouth, stomach, and small intestine). As Harvard Health summarizes it, “Once nutrients are broken into small enough molecules, they are absorbed through the wall of the small intestine and then delivered throughout the body.” “Digestive enzymes” is also often used to describe digestive enzyme supplements—a corner of the alternative health market that’s expected to reach $1.6 billion by 2025 and which are used to help manage everything from flatulence and bloating to overall gut health.


…is an often-agonizing condition in which pockets that form on the lining of the digestive system (called diverticula) become inflamed or infected. Distinguished by symptoms that include persistent pain (particularly on one side of the abdomen), nausea and vomiting, fever, tummy tenderness, and constipation (and, more unusually, diarrhea), its risk factors include aging, smoking, a lack of exercise, obesity, a diet high in animal fat and low in fiber, and certain medications, such as Aleve and steroids.


…is the medical term for difficulty swallowing, as well as the sensation of food being stuck in your chest (behind your breast bone) or esophagus. Often caused by seemingly minor events—such as laughing while eating, eating too fast, or not chewing well enough—it often resolves on its own and usually isn’t cause for concern. Persistent dysphagia, however, may indicate a serious medical condition.


…is a non-surgical procedure in which your digestive tract can be viewed with a flexible tube with a light and camera attached. Physicians recommend an endoscopy to evaluate stomach pain, changes in bowel habits (such as constipation), polyps or growths, ulcers, digestive tract bleeding, and overall abdominal pain.


…is a form of material found in carbohydrates that cannot be digested by the human body but that is—however counterintuitively—vital to digestion. (Fiber also assists in the way your body handles sugars, which helps keep hunger and blood sugar in check.) Two types of fiber exist: soluble fiber and non-soluble (or insoluble) fiber. The former—which is found in apples, blueberries, oatmeal, nuts, and more—dissolves in water and can promote lower glucose and blood cholesterol levels. The latter—which is found in brown rice, whole wheat bread, carrots, tomatoes, and more—does not dissolve in water, and can naturally encourage regularity and prevent constipation.


…is frequently deemed one of the best natural therapies for digestion. A flowering plant that originates in China, ginger contains a bioactive compound called gingerol, which is often used to help manage the symptoms of nausea (including nausea from morning sickness) and indigestion.

Lactose intolerance

…refers to a digestive disorder caused by an incapacity to tolerate lactose—the chief carbohydrate in dairy foods (which requires adequate levels of the enzyme lactase to digest). Affecting nearly 65 percent of the human population, its symptoms include bloating, diarrhea and cramps.

Celiac disease

…is a digestive disorder that affects the small intestine. While experts are unclear what causes the disorder, research suggests that it carries a strong genetic link—and only affects people who eat gluten, a protein found in wheat, barley, and rye. (As such, people with celiac disease cannot eat gluten.) The symptoms of celiac disease overlap with other digestive disorders—such as nausea and bloating—and, if not managed, can cause long-term digestion problems and the malnutrition that arrives with it.


…is another enzyme critical to digestion. Found naturally in the body, it helps break down fats into fatty acids and glycerol—products that are carried into fluids (such as blood) and ultimately used to supply energy.


…would be one of the most important organs in your body. Situated on the right hand side of the body, and weighing in at approximately three pounds, it plays a fundamental role in digesting, absorbing, and processing food. It also filters blood from the digestive tract before it’s passed into the rest of your body. Further, the liver detoxifies chemicals, metabolizes drugs and produces proteins that are essential to blood clotting.


…represents a group of digestive disorders in which the small intestine can’t absorb adequate amounts of certain nutrients and fluids. Caused by a number of factors—including lactose intolerance, celiac disease and prolonged use of antibiotics—its symptoms range from hair loss and fluid retention to weight loss. Dietary changes, vitamin supplements and enzyme supplements are often used to address it.


…is the 6-inch-long organ that sits behind your stomach in the back of your abdomen. Connected to the small intestine, it, too, has a major role in digestion, in that it helps convert the food you eat into energy and moderates blood sugar.


…stands for the enzyme that breaks down proteins (such as meat, dairy, eggs and seeds) into what’s known as peptides, which act as both neurotransmitters and hormones—and are central to your body’s ability to function efficiently.


…is another vital enzyme. By helping your body break down protein into amino acids—which then provide fuel—proteases also impact cell division, blood clotting, the recycling of proteins and immunity. Research reveals that proteases can also encourage digestion and wound healing.


…are not to be confused with probiotics (see below) but are deserving of just as much attention. Classified as a non-digestible fiber also known as oligosaccharides, they operate as “food” for probiotics, and organically support digestive health by fermenting in the gut flora. Found in a number of high-fiber foods—including fruits, vegetables and whole grains—they’re provided to babies through the sugar produced in breast milk. Increasing your intake of prebiotics has been shown to support hormone equilibrium, overall gut health and cholesterol levels.


…refer to the live bacteria that line your digestive tract and foster your ability to absorb nutrients and transform them into fuel. They also assist in fighting off infections, maintaining skin health, and bolstering digestion. Diminished by emotional stress, sugar, GMO foods, alcohol and smoking, they can be restored—and overall boosted—by frequently eating “probiotic” foods such as kimchee, miso, yogurt, and natto. You can also increase probiotics through probiotic supplements.


…is a hole or break in the protective lining of the small intestine or the stomach. Striking nearly one in every ten American at some point in their lives, ulcers are predominately characterized by the gnawing, burning sensation they create. (Other symptoms include weight loss, acid reflux, and nausea.) Once thought to be caused by a build-up of stomach acid from excess caffeine and overindulging in rich, fatty foods, new research demonstrates that ulcers are caused by bacterial infections, as well as the overuse of OTC painkillers (such as ibuprofen), stress and heavy alcohol use. Often easily treatable, they’re nonetheless painful—and serve as another reminder to start prioritizing your digestive health today.

These statements have not been approved by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent disease.