A–Z index of GI conditions

Achalasia is a rare but serious esophageal motility disorder in which the lower esophageal sphincter (LES) fails to relax during swallowing and the esophagus loses its co-ordinated peristaltic contractions. Food and liquid accumulate in the esophagus rather than passing into the stomach, causing progressive difficulty swallowing. It results from the loss of inhibitory neurons in the esophageal myenteric plexus (Auerbach's plexus). While there is no cure, achalasia is very effectively managed by endoscopic procedures (pneumatic dilation or POEM) or laparoscopic Heller myotomy.

Adalimumab is a fully human monoclonal antibody that targets TNF-α. Unlike infliximab, it is given as a self-administered subcutaneous injection, making it more convenient for many patients. It is approved for Crohn's disease and ulcerative colitis, as well as several other inflammatory conditions.

An anal fissure is a small tear in the thin, moist tissue lining the anal canal. It is one of the most common causes of painful bowel movements and rectal bleeding. Most fissures are caused by trauma from hard or large stools. Acute fissures usually heal within a few weeks; chronic fissures (lasting more than 8 weeks) require medical treatment.

Barrett's esophagus is a condition where the normal lining of the esophagus changes to resemble the lining of the intestine — usually as a result of long-standing acid reflux (GERD). It is important because it slightly increases the risk of esophageal adenocarcinoma. Most people with Barrett's esophagus never develop cancer, but regular monitoring is essential.

Bile acid malabsorption (BAM) — also called bile acid diarrhoea — occurs when bile acids that should be reabsorbed in the terminal ileum instead spill into the colon, where they stimulate water and electrolyte secretion and accelerate colonic motility, causing chronic watery diarrhoea. BAM is estimated to be responsible for up to 30% of cases labelled as diarrhoea-predominant IBS (IBS-D) and is profoundly under-diagnosed. Primary (type 2) BAM involves idiopathic hepatic overproduction of bile acids. Secondary (type 1 and 3) BAM follows Crohn's disease of the ileum, ileal resection, cholecystectomy, or radiation.

Bloating is that uncomfortable feeling of fullness or swelling in your abdomen. Everyone experiences it occasionally, but persistent bloating can be a sign of an underlying condition like IBS, SIBO, lactose intolerance, or celiac disease. The good news is that most causes are treatable.

Celiac disease is an autoimmune condition where eating gluten — a protein found in wheat, barley, and rye — triggers your immune system to attack the lining of your small intestine. This damages the tiny finger-like projections (villi) that absorb nutrients, leading to malnutrition, anemia, and a wide range of symptoms. About 1% of people worldwide have it, but it is often undiagnosed for years. The only treatment is a strict, lifelong gluten-free diet — but with that, the intestine heals and symptoms resolve.

Certolizumab pegol is a PEGylated Fab' fragment of a humanised anti-TNF-α antibody. Unlike other anti-TNF agents, it lacks an Fc region, which means it does not activate complement or cause antibody-dependent cell-mediated cytotoxicity. It is approved for Crohn's disease and is notably used in pregnancy because minimal drug crosses the placenta.

Colorectal cancer is one of the most preventable cancers. It usually starts as small, non-cancerous polyps that grow slowly over 10–15 years before becoming cancer. Regular screening (colonoscopy) can find and remove these polyps before they turn dangerous. Screening saves lives — it's that simple.

Colon polyps are small clumps of cells that form on the lining of the colon. Most polyps are harmless (hyperplastic or inflammatory), but some types — particularly adenomas — can slowly develop into colorectal cancer over 10–15 years. That is why colonoscopy screening is so important: finding and removing polyps before they become cancerous is the single most effective way to prevent colon cancer.

Colonoscopy is a 20–30 minute procedure where a thin, flexible tube with a tiny camera is passed through the rectum to examine the entire large intestine. It's the gold standard for detecting and removing colon polyps before they turn into cancer, and for diagnosing causes of bleeding, chronic diarrhea, or anemia. You'll be sedated and comfortable throughout. The success of the test depends almost entirely on how well your colon is cleaned out beforehand — that's why preparation is so important.

Constipation means having fewer than three bowel movements per week, or stools that are hard, dry, and difficult to pass. It's one of the most common digestive complaints and is usually not serious — but chronic constipation can significantly affect your quality of life.

Crohn's disease is a chronic inflammatory bowel disease (IBD) that can affect any part of your digestive tract from your mouth to your anus, though it most commonly affects the end of the small intestine and the beginning of the large intestine. It causes inflammation that goes deep into the layers of affected bowel tissue, leading to pain, severe diarrhea, malnutrition, and other complications.

Diarrhea means passing loose or watery stools three or more times a day. Most cases are acute (lasting 1–2 days) and resolve on their own. But chronic diarrhea (lasting more than 4 weeks) needs medical evaluation. The biggest immediate risk is dehydration, especially in children and the elderly.

Dietary therapy is one of the most effective treatments for eosinophilic esophagitis (EoE), achieving histological remission (fewer than 15 eosinophils per high-power field on biopsy) in 50–80% of patients without the need for long-term medication. The goal is to systematically eliminate the food antigens driving eosinophilic inflammation and then reintroduce them one at a time to identify individual triggers. The three main strategies — from most to least restrictive — are: the 6-food elimination diet (6-FED), the 4-food elimination diet (4-FED), and the targeted 2-food elimination diet (2-FED, removing only milk and wheat).

Dysphagia means difficulty swallowing — food or liquid takes extra effort or time to move from your mouth to your stomach. It can feel like food is stuck in your throat or chest. While occasional difficulty is usually nothing to worry about, persistent dysphagia needs evaluation as it may indicate an esophageal or neurological condition.

Diverticular disease occurs when small pouches (diverticula) form in weak spots of the colon wall. Most people with diverticula (diverticulosis) have no symptoms. When these pouches become inflamed or infected, the condition is called diverticulitis — which can cause significant pain and requires medical treatment.

Dupilumab is a biologic that blocks IL-4 and IL-13 signalling by targeting the IL-4Rα receptor subunit. It is best known for atopic dermatitis and asthma, but is also approved for eosinophilic esophagitis (EoE) — a condition where eosinophil-driven inflammation causes difficulty swallowing and chest pain. It is given as subcutaneous injections.

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease where a type of white blood cell (eosinophil) builds up in the esophagus, causing inflammation. It is triggered by food allergens and/or environmental allergens. EoE can affect children and adults, often causing difficulty swallowing and food getting stuck.

Esophageal stricture is a narrowing of the esophageal lumen that causes progressive difficulty swallowing (dysphagia). It is classified as benign — most commonly caused by chronic GERD (peptic stricture), eosinophilic esophagitis, or surgical scarring — or malignant (esophageal cancer), which must always be urgently excluded. Most benign strictures are effectively managed by endoscopic dilation (balloon or bougie), often combined with treatment of the underlying cause. Inadequate treatment of the root cause invariably leads to stricture recurrence.

Fatty liver disease (NAFLD) means too much fat is stored in your liver cells. It's the most common liver condition worldwide. Most people have no symptoms, but over time it can progress to inflammation (NASH), scarring (fibrosis), and even cirrhosis. The good news: early-stage fatty liver is reversible with lifestyle changes.

Fecal incontinence — the involuntary loss of control over bowel movements, causing unintended leakage of stool — affects up to 10% of adults and is profoundly under-reported because of embarrassment and the mistaken belief that it is an inevitable part of ageing. It has a severe impact on quality of life, employment, and social participation. The underlying causes include sphincter muscle damage, nerve damage, diarrhoea, and pelvic floor dysfunction. Thorough evaluation with anorectal manometry and endoanal ultrasound guides treatment, which ranges from dietary modifications and biofeedback to sacral nerve stimulation.

Fiber is one of the most important nutrients for digestive health. It's the part of plant foods that your body can't digest — and that's exactly what makes it so valuable. It feeds your healthy gut bacteria, keeps bowel movements regular, helps control blood sugar, and even reduces the risk of colon cancer.

Filgotinib is a preferential JAK1 inhibitor taken as a once-daily oral tablet, approved for moderate-to-severe ulcerative colitis. Its preferential selectivity for JAK1 over other JAK enzymes aims to balance efficacy with a more targeted safety profile.

Functional anorectal pain encompasses two Rome IV-defined disorders: proctalgia fugax (sudden, severe, brief episodes of rectal pain lasting from seconds to a few minutes, then resolving completely) and levator ani syndrome (a dull aching pressure or discomfort in the rectum or pelvis lasting 20 minutes or longer). Both have no identifiable structural cause and are benign, but the episodes are intensely distressing. They are commonly misdiagnosed as haemorrhoids, anal fissure, or prostatitis and require thorough structural exclusion before a functional diagnosis is confirmed.

Functional constipation is chronic constipation without an identifiable structural, biochemical, or medication-related cause. Defined by the Rome IV criteria, it is diagnosed when a patient has two or more of the following for at least 3 months: straining in more than 25% of defecations, lumpy or hard stools, sensation of incomplete evacuation, sensation of anorectal obstruction, need for manual manoeuvres, or fewer than 3 spontaneous bowel movements per week. It is among the most prevalent GI disorders worldwide and is distinct from irritable bowel syndrome with constipation (IBS-C) in that abdominal pain or discomfort is NOT the predominant feature.

Functional dyspepsia (FD) is chronic upper abdominal discomfort — pain, burning, early fullness, or bloating after eating — with no structural cause found on endoscopy or imaging. It affects up to 20% of adults worldwide. While not dangerous, FD can significantly impair daily life and is often confused with GERD or ulcers.

Gallstones are hard deposits that form in your gallbladder — a small organ under your liver that stores bile. They range from the size of a grain of sand to a golf ball. Many people have gallstones with no symptoms ("silent stones"), but when a stone blocks a bile duct, it causes sudden, intense pain called a gallbladder attack.

A gastric balloon (also called intragastric balloon) is a soft silicone balloon placed in the stomach during a 20-minute endoscopy and filled with sterile saline. It takes up space, makes you feel full faster, and helps you eat smaller portions — supporting weight loss of typically 10–20 kg over 6 months. It's a non-surgical, reversible option for people with a BMI between 27 and 40 who want a structured kick-start to weight loss alongside diet and lifestyle change. The balloon is removed (also by endoscopy) at 6 months.

Gastric intestinal metaplasia (GIM) is a precancerous change in the stomach lining in which the normal gastric glandular epithelium is replaced by intestine-type cells. It represents an intermediate step on the Correa cascade: normal mucosa → chronic gastritis → atrophic gastritis → intestinal metaplasia → dysplasia → gastric adenocarcinoma. While most people with GIM never develop cancer, it confers a 6-fold increased risk of gastric cancer, making surveillance essential. The primary driver is H. pylori infection, and eradicating it can halt or partially reverse the process.

Gastroparesis means the stomach takes much longer than normal to empty its contents into the small intestine — without any physical blockage. It is most commonly caused by diabetes, but can also follow viral illness or stomach surgery. Symptoms are chronic and can significantly impact quality of life and nutrition.

IBD and other GI disorders are treated with a wide spectrum of medications. Beyond biologics and small molecules, the following classes form the backbone of traditional drug therapy. Understanding how each medication works and when it is used helps you participate actively in your treatment decisions.

Golimumab is a fully human anti-TNF-α monoclonal antibody approved specifically for ulcerative colitis (the only anti-TNF in IBD given as a monthly subcutaneous injection). It is also approved for rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis.

Helicobacter pylori (H. pylori) is a spiral-shaped bacterium that infects the stomach lining of about half of the world's population — and is especially common in Saudi Arabia and the wider Middle East. Most people have no symptoms, but in others it causes chronic gastritis, peptic ulcers, and a small but real increase in the risk of stomach cancer. The good news: it can almost always be cured with a 10–14 day course of antibiotics combined with acid-suppressing medication.

What you eat directly affects your digestive health. A balanced diet rich in fiber, prebiotics, and probiotics supports healthy gut bacteria and smooth digestion. On the other hand, processed foods, excess sugar, and low fiber intake can lead to constipation, bloating, and inflammation.

Heartburn is a burning feeling in your chest, behind the breastbone. It happens when stomach acid flows back up into your esophagus (food pipe). Occasional heartburn is common, but frequent heartburn (more than twice a week) may be a sign of GERD (gastroesophageal reflux disease).

Hemorrhoids are swollen blood vessels in the rectum or anus — similar to varicose veins. They're extremely common (about half of adults experience them by age 50). They can cause bleeding, itching, and discomfort, but are rarely dangerous. Most cases improve with simple lifestyle changes.

Hepatitis B is a viral infection of the liver caused by the hepatitis B virus (HBV). About 5% of adults exposed develop chronic infection that can quietly damage the liver over decades, leading to cirrhosis or liver cancer. Most people have no symptoms in the early years — the only way to know is a blood test. There is a highly effective vaccine that prevents it, and modern medications can keep chronic infection well-controlled, although a complete cure for chronic HBV is not yet available.

Hepatitis C is a viral liver infection that, until recently, had no good treatment — but that changed completely. Today's direct-acting antiviral (DAA) medications cure more than 95% of cases in a simple 8–12 week course of pills, with very few side effects. About 70% of people exposed develop chronic infection, often without symptoms for years, while quietly causing liver scarring. If you were born before 1990, had a blood transfusion before 1995, or have unexplained liver enzyme elevation — get tested. Cure is now within reach.

Managing inflammatory bowel disease (Crohn's disease and ulcerative colitis) often requires medications to reduce inflammation, suppress the immune system, and control symptoms. There are several classes of medications used to treat IBD, ranging from aminosalicylates for mild disease to biologic therapies for moderate to severe cases. Finding the right medication regimen is key to achieving and maintaining remission.

Infliximab is a chimeric monoclonal antibody that targets tumour necrosis factor-alpha (TNF-α), a key protein driving inflammation in IBD. It was the first biologic approved for Crohn's disease and ulcerative colitis and remains one of the most widely used. It is given as an intravenous infusion in a clinic or hospital setting.

IBS is a common condition that affects the large intestine. It causes cramping, bloating, gas, and changes in bowel habits (diarrhea, constipation, or both). IBS doesn't damage the intestine or increase cancer risk, but it can be very uncomfortable. The good news: it's manageable with the right approach.

Lactose intolerance means your body can't fully digest lactose — the sugar found in milk and dairy products. This happens because you don't produce enough lactase, the enzyme that breaks down lactose. It's very common (especially in the Middle East) and is not the same as a milk allergy. It's not dangerous, but can be uncomfortable.

Cirrhosis is the late stage of scarring (fibrosis) of the liver caused by long-term liver damage. Common causes include chronic viral hepatitis (B and C), fatty liver disease (MASLD), and alcohol. Once cirrhosis develops, the scarring is largely irreversible, but stopping the cause can slow progression and prevent complications.

Microscopic colitis is a common but under-recognised cause of chronic, watery, non-bloody diarrhoea, particularly in middle-aged and older adults. Despite causing significant symptoms, the colon appears completely normal on colonoscopy — the diagnosis is made only on microscopic examination of mucosal biopsies. There are two histological subtypes: collagenous colitis (characterised by a thickened subepithelial collagen band) and lymphocytic colitis (excess intraepithelial lymphocytes). It is strongly associated with NSAID use, proton-pump inhibitors (particularly lansoprazole), and certain antidepressants. Budesonide is the most effective treatment.

Mirikizumab is one of the newest IBD biologics, selectively targeting IL-23 p19 (like risankizumab). It is approved for moderate-to-severe ulcerative colitis. Induction is given as IV infusions, followed by subcutaneous maintenance injections.

Nausea is that queasy, unsettled feeling in your stomach that makes you feel like you might vomit. It's not a disease itself but a symptom of many conditions. Most episodes are temporary and harmless, but persistent or severe nausea needs evaluation to find the underlying cause.

Obesity doesn't just affect your heart and joints — it has a major impact on your digestive system. Excess weight increases pressure on the abdomen, which can worsen acid reflux, contribute to fatty liver disease, increase the risk of gallstones, and raise your chances of developing colon cancer.

Pancreatitis is inflammation of the pancreas — the gland that produces digestive enzymes and insulin. Acute pancreatitis comes on suddenly and usually resolves with treatment, while chronic pancreatitis develops slowly over time and can permanently damage the pancreas. Gallstones and alcohol are the two most common causes.

Pelvic floor dysfunction (PFD) occurs when the muscles of the pelvic floor — which support the bladder, bowel, and uterus or prostate — fail to coordinate properly during defecation. The most common GI form is dyssynergic defecation (anismus), where the pelvic floor muscles paradoxically contract instead of relaxing during straining, making it difficult or impossible to pass stool. PFD is frequently misdiagnosed as simple constipation and often coexists with irritable bowel syndrome. Biofeedback therapy achieves remission in 70–80% of patients.

Proton pump inhibitors (PPIs) are among the most widely used medications in gastroenterology. They work by blocking the proton pump (H⁺/K⁺-ATPase) in the stomach wall cells, effectively reducing acid production. This class includes omeprazole (Losec), pantoprazole (Protonix), esomeprazole (Nexium), lansoprazole (Prevacid), and rabeprazole (Aciphex). They are safe and effective when used with proper medical guidance.

Risankizumab is a newer biologic that selectively targets IL-23 (specifically its p19 subunit) without blocking IL-12, providing more targeted suppression of the Th17 inflammatory pathway. It is approved for moderate-to-severe Crohn's disease and ulcerative colitis.

SIBO occurs when bacteria that normally live in the large intestine colonize the small intestine in excessive numbers. This interferes with normal digestion and nutrient absorption. SIBO is increasingly recognized as an underlying cause of IBS-like symptoms and nutritional deficiencies.

Stomach ulcers are open sores that develop on the lining of the stomach or the upper part of the small intestine. They occur when the protective mucus layer is reduced, allowing digestive acids to eat away at the tissue. The two most common causes are H. pylori infection and long-term use of NSAIDs (like ibuprofen).

Tofacitinib is a JAK (Janus kinase) inhibitor — a small molecule oral medication that broadly suppresses multiple inflammatory pathways. Unlike biologics, it is taken as a tablet twice daily. It is approved for ulcerative colitis and acts quickly, making it useful for patients who need rapid disease control.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease that affects the colon and rectum. It causes inflammation and ulcers (sores) in the innermost lining of the large intestine, leading to symptoms like diarrhea, rectal bleeding, and abdominal pain. Unlike Crohn's disease, UC inflammation is limited to the colon and does not extend through all layers of the bowel wall.

Upadacitinib is a selective JAK1 inhibitor taken as a once-daily oral tablet. Compared to tofacitinib, its selectivity for JAK1 aims to provide efficacy while reducing off-target effects. It is approved for moderate-to-severe Crohn's disease and ulcerative colitis.

An upper endoscopy (also called EGD or gastroscopy) is a 10–15 minute procedure where a thin, flexible camera is passed through the mouth to examine the esophagus, stomach, and the first part of the small intestine (duodenum). It's used to investigate heartburn, swallowing problems, abdominal pain, anemia, or suspected ulcers — and it can take biopsies to test for H. pylori, celiac disease, or pre-cancerous changes (Barrett's esophagus). You'll be sedated through an IV and feel almost nothing.

Ustekinumab is a biologic that targets interleukins IL-12 and IL-23 — key cytokines in the inflammatory cascade of Crohn's disease and ulcerative colitis. It is given as a single intravenous dose for induction, then as subcutaneous injections for maintenance every 8 or 12 weeks.

Vedolizumab is a gut-selective biologic that targets the α4β7 integrin on immune cells, preventing them from entering the intestinal lining. Because its action is confined to the gut, it has a favourable safety profile — particularly regarding infections — compared to systemic biologics. It is given as an intravenous infusion.