IBD Glossary
Understanding IBD, One Term at a Time
Medical language can make an IBD diagnosis feel even more overwhelming.
Explore plain-language explanations of words you may encounter during appointments, in test results and throughout your IBD journey.
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Glossary Terms
Showing all 44 terms
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A
Abscess
What it means:
A collection of pus that develops because of an infection.
Why you may hear it:
Abscesses can occur as a complication of Crohn’s disease, including around the intestine or anal area. They require evaluation and treatment by qualified healthcare professionals.
Anemia
What it means:
A condition in which the blood does not carry as much oxygen as the body needs, often because there are too few healthy red blood cells or too little hemoglobin.
Why you may hear it:
People with IBD may be evaluated for anemia because of blood loss, inflammation, reduced nutrient absorption or other causes. Fatigue can have many causes and should not be assumed to mean anemia without appropriate evaluation.
Antibody
What it means:
A protein made by the immune system that recognizes a specific target.
Why you may hear it:
Antibodies may be discussed in laboratory testing and in relation to certain biologic treatments. Some biologic medicines are laboratory-produced antibodies designed to act on specific parts of the immune response.
B
Biologic
What it means:
A type of medical product made from living sources or using biological processes. Biologic medications are generally more complex than traditional chemically produced drugs.
Why you may hear it:
Several biologic medicines are approved to treat Crohn’s disease and ulcerative colitis by targeting particular parts of the immune response. Treatment decisions belong between patients and qualified healthcare professionals.
Biosimilar
What it means:
An FDA-approved biologic medication that is highly similar to an already approved biologic, called the reference product, with no clinically meaningful differences in safety or effectiveness.
Why you may hear it:
A patient may receive or transition to a biosimilar because of availability, insurance coverage or other treatment considerations. A biosimilar is not the same as a generic drug, although both are compared with previously approved products.
Biopsy
What it means:
A small sample of tissue removed so it can be examined under a microscope.
Why you may hear it:
During a colonoscopy or endoscopy, a clinician may take biopsies to look for inflammation, tissue changes or other findings. A biopsy does not necessarily mean cancer is suspected.
C
Calprotectin
What it means:
A protein associated with inflammation. Fecal calprotectin is measured in a stool sample.
Why you may hear it:
Healthcare professionals may use fecal calprotectin as one piece of information when evaluating or monitoring intestinal inflammation. Results must be interpreted in the context of symptoms, health history and other testing.
Digestive Harmony does not interpret calprotectin values or define what a particular result means for an individual.
Clinical Trial
What it means:
A research study involving people that evaluates health-related questions, such as the safety or effectiveness of a treatment, test or care approach.
Why you may hear it:
Clinical trials help researchers learn more about IBD. A study listing does not mean participation is appropriate for everyone. Eligibility, possible benefits, risks and alternatives should be discussed with the research team and appropriate healthcare professionals.
Colon
What it means:
The main part of the large intestine. It receives material from the small intestine and helps absorb water and form stool.
Why you may hear it:
Ulcerative colitis affects the colon and rectum. Crohn’s disease can also affect the colon, although it may involve other parts of the digestive tract.
Colonoscopy
What it means:
A procedure that uses a thin, flexible tube with a camera to examine the rectum and colon. The end of the small intestine may also be examined in some procedures.
Why you may hear it:
Colonoscopy may be used to help diagnose IBD, assess inflammation, obtain biopsies or perform recommended surveillance. Preparation instructions differ, so patients should follow the directions provided by their own healthcare facility.
Corticosteroid
What it means:
A type of medication that reduces inflammation and affects immune activity. It is different from anabolic steroids used for muscle building.
Why you may hear it:
Corticosteroids may be used for limited periods to control active IBD. Because they can have significant effects and are generally not intended as long-term maintenance treatment for IBD, they must be used under medical supervision.
C-Reactive Protein
What it means:
A protein made by the liver that can increase when inflammation is present in the body. It is commonly abbreviated as CRP.
Why you may hear it:
A blood CRP test may be considered alongside symptoms and other tests when evaluating inflammation. CRP is not specific to IBD, and an individual result requires professional interpretation.
Crohn’s Disease
What it means:
A chronic inflammatory bowel disease that can affect any part of the digestive tract, from the mouth to the anus. It commonly affects the end of the small intestine, the colon or both.
Why you may hear it:
Crohn’s disease and ulcerative colitis are the two main forms of IBD. Crohn’s inflammation can extend through multiple layers of the bowel wall and may occur in separated areas.
E
Endoscopy
What it means:
A general term for procedures that use a flexible viewing instrument to examine the inside of the digestive tract.
Why you may hear it:
Upper endoscopy examines the upper digestive tract, while colonoscopy examines the rectum and colon. Endoscopy may be used to evaluate symptoms, assess inflammation or obtain biopsies.
Enterography
What it means:
A type of imaging designed to provide detailed pictures of the small intestine. It may be performed using magnetic resonance imaging or computed tomography.
Why you may hear it:
MR enterography or CT enterography may be used when clinicians need information about the small bowel and areas outside the intestinal lining. The appropriate test and preparation depend on individual circumstances.
Extraintestinal Manifestation
What it means:
A health effect associated with IBD that occurs outside the digestive tract.
Why you may hear it:
IBD can sometimes affect areas such as the joints, skin, eyes or liver. Symptoms outside the digestive system can have many causes and require appropriate evaluation.
Often abbreviated as EIM.
F
Fistula
What it means:
An abnormal passage connecting two parts of the body that are not normally connected.
Why you may hear it:
Crohn’s disease can sometimes lead to fistulas between parts of the intestine or between the intestine and another organ or the skin. Perianal fistulas develop near the anus.
Flare
What it means:
A period when IBD symptoms or disease activity increase after a period of improvement or stability.
Why you may hear it:
Patients and healthcare professionals may use “flare” in different ways. Symptoms can increase for reasons other than active intestinal inflammation, so changing symptoms may require professional evaluation rather than self-diagnosis.
G
Gastroenterologist
What it means:
A physician who specializes in conditions affecting the digestive system.
Why you may hear it:
Gastroenterologists diagnose and manage Crohn’s disease and ulcerative colitis, often working with nurses, dietitians, surgeons, pharmacists and other professionals.
Gastrointestinal Tract
What it means:
The connected series of organs through which food and liquids travel, beginning at the mouth and ending at the anus.
Why you may hear it:
The gastrointestinal tract includes the esophagus, stomach, small intestine, large intestine, rectum and anus. It is often abbreviated as the **GI tract** or called the digestive tract.
I
Ileum
What it means:
The final section of the small intestine, located before the large intestine.
Why you may hear it:
The ileum is a common location for Crohn’s disease. A clinician may use the term “terminal ileum” to describe its last portion.
Ileostomy
What it means:
A surgically created opening that brings the end of the small intestine through the abdominal wall so waste can leave the body through a stoma.
Why you may hear it:
An ileostomy may be temporary or permanent depending on the operation and individual circumstances. Waste is collected in an external ostomy pouch.
Immune System
What it means:
The body’s network of cells, tissues and organs that helps defend against infection and other threats.
Why you may hear it:
IBD involves abnormal immune responses that contribute to ongoing inflammation in the digestive tract. This does not mean that IBD is caused by something the patient did.
Immunomodulator
What it means:
A medication that changes or regulates immune-system activity.
Why you may hear it:
Some immunomodulators are used in IBD treatment. Different medicines work in different ways and have different benefits, risks and monitoring requirements.
Inflammation
What it means:
A biological response involving the immune system. Inflammation can help protect the body, but persistent or misdirected inflammation can damage tissue.
Why you may hear it:
Crohn’s disease and ulcerative colitis involve chronic inflammation in the digestive tract. Symptoms alone cannot always determine how much inflammation is present.
Inflammatory Bowel Disease
What it means:
A group of chronic conditions involving inflammation in the digestive tract. The two main forms are Crohn’s disease and ulcerative colitis.
Why you may hear it:
Inflammatory bowel disease is commonly abbreviated as **IBD**. It is different from irritable bowel syndrome, or IBS, although some symptoms may overlap.
Infusion
What it means:
A method of delivering medication or fluid into a vein over a period of time.
Why you may hear it:
Some IBD biologic medications are given at an infusion center, clinic or other healthcare facility. The schedule and process depend on the specific medicine and care setting.
L
Large Intestine
What it means:
The part of the digestive tract that includes the colon and rectum and helps absorb water and form stool.
Why you may hear it:
Ulcerative colitis affects the inner lining of the large intestine. Crohn’s disease can also involve the large intestine.
M
Maintenance Therapy
What it means:
Ongoing treatment intended to help maintain disease control or remission.
Why you may hear it:
IBD treatment may include a plan for controlling active disease and a longer-term plan for maintaining improvement. Maintenance treatment should be followed as directed by the healthcare team.
Malabsorption
What it means:
Reduced absorption of nutrients from food as it moves through the digestive tract.
Why you may hear it:
Small-intestinal inflammation, surgery and other health circumstances may affect nutrient absorption in some people with IBD. Nutritional concerns require individualized evaluation.
Mucosa
What it means:
The moist inner lining of parts of the body, including the digestive tract.
Why you may hear it:
During endoscopy, clinicians examine the intestinal mucosa for inflammation, ulcers and other changes.
Mucosal Healing
What it means:
Improvement or resolution of visible inflammation in the intestinal lining, generally assessed through endoscopy.
Why you may hear it:
Mucosal healing may be discussed as a treatment goal or monitoring finding. It does not mean IBD has been cured, and its meaning depends on the clinical context.
O
Ostomy
What it means:
A surgically created opening that allows bodily waste to leave through the abdominal wall.
Why you may hear it:
Some people with IBD have an ileostomy or colostomy after surgery. An ostomy may be temporary or permanent depending on individual circumstances.
P
Perianal Disease
What it means:
Disease or complications affecting the area around the anus.
Why you may hear it:
In Crohn’s disease, perianal involvement may include fistulas, abscesses, fissures or other concerns. Symptoms in this area deserve appropriate medical evaluation.
Proctitis
What it means:
Inflammation of the rectum.
Why you may hear it:
Ulcerative proctitis is ulcerative colitis limited to the rectum. Proctitis can also have other causes, so the term alone does not establish an IBD diagnosis.
R
Remission
What it means:
A period in which the signs, symptoms or measurable activity of a disease are reduced or absent.
Why you may hear it:
IBD remission may be described in different ways, such as clinical, biochemical or endoscopic remission. Remission does not mean that IBD has been permanently cured.
Resection
What it means:
Surgery to remove part of an organ or tissue.
Why you may hear it:
In IBD, bowel resection removes a diseased or complicated section of intestine. The remaining sections may be reconnected or an ostomy may be created, depending on the procedure.
S
Small Bowel
What it means:
Another name for the small intestine, the long section of digestive tract between the stomach and large intestine.
Why you may hear it:
The small bowel includes the duodenum, jejunum and ileum. Crohn’s disease can affect one or more areas of the small bowel.
Stoma
What it means:
A surgically created opening on the abdomen that allows waste to leave the body.
Why you may hear it:
A stoma is created during ostomy surgery. An ostomy pouch fits over the stoma to collect waste.
Stool Test
What it means:
A laboratory test performed on a sample of stool.
Why you may hear it:
Stool tests may be used to look for signs of intestinal inflammation, infection or other conditions. Different tests answer different questions and require professional interpretation.
Stricture
What it means:
An abnormal narrowing in part of the digestive tract.
Why you may hear it:
In Crohn’s disease, inflammation or scar tissue may narrow part of the intestine and interfere with movement through the bowel. Management depends on the cause, location and severity.
T
Therapeutic Drug Monitoring
What it means:
Testing used to measure the amount of certain medication in the blood and, in some cases, antibodies associated with that medication.
Why you may hear it:
Healthcare professionals may use therapeutic drug monitoring as one part of evaluating treatment. Results must be interpreted with the medication, timing, symptoms and other clinical information.
Often abbreviated as TDM.
U
Ulcer
What it means:
An open sore in the lining of the body, including the digestive tract.
Why you may hear it:
Ulcers may be seen during endoscopy when inflammation has damaged the intestinal lining. The cause and significance depend on the individual situation.
Ulcerative Colitis
What it means:
A chronic inflammatory bowel disease that causes inflammation and ulcers in the inner lining of the large intestine.
Why you may hear it:
Ulcerative colitis begins in the rectum and may extend continuously through part or all of the colon. It is one of the two main forms of IBD.
About These Definitions
Digestive Harmony develops glossary definitions using established government health information, regulatory resources and recognized IBD patient-education sources.
Definitions are written in plain language and are intended to help visitors understand terminology—not interpret individual symptoms, laboratory results, pathology reports or treatment recommendations.
Terms and source links should be reviewed periodically because medical language and guidance can evolve.
Last reviewed: [Month Year]
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