A gastrointestinal (GI) disease affects your digestive tract—the path food and drink take through your body and the digestive organs. GI diseases can impact your esophagus (the tube running down from the throat), stomach, liver, gallbladder, pancreas, and small and large intestine.

Gastrointestinal diseases range from mild to severe and can be acute or chronic. They’re common, with research estimating about 20% of people in the United States have at least one gastrointestinal disease. Because GI organs serve such critical functions, it’s important to understand gastrointestinal diseases and how to treat them. 

There are two categories of gastrointestinal diseases: functional and structural diseases.

Functional GI diseases affect how the digestive tract works but do not leave any physical signs of disease on the organs. Structural GI diseases arise due to physical problems along the digestive tract. 

Functional Gastrointestinal Diseases

Functional gastrointestinal diseases occur due to miscommunication between the brain and gut, leading to abnormal digestive tract function. There are many functional GI diseases—33 in adults and 20 that impact children—which can affect any part of the GI tract.

The most common functional GI diseases include: 

• Irritable bowel syndrome (IBS): IBS refers to a group of symptoms of the abdomen and intestines, causing pain and problems with bowel movements.
• Functional dyspepsia: A common functional GI disorder, dyspepsia (upset stomach) causes chronic indigestion.
• Functional vomiting and nausea: This condition is defined as experiencing nausea or vomiting at least twice a week for at least two months, not due to eating patterns or other medical conditions. 
• Functional abdominal pain: This is a pain in the abdomen unrelated to other health conditions, diet, physical activity, or body position. It often accompanies other diseases and symptoms, such as nausea and diarrhea.
• Functional diarrhea: Watery, loose stools can indicate another condition. When it arises on its own, it’s considered a functional GI disease.

Structural Gastrointestinal Diseases

Structural GI diseases are disorders caused by structural problems within the gastrointestinal tract. Some examples of these conditions are:

• Gastroesophageal reflux disease (GERD): GERD is a long-lasting type of gastroesophageal reflux (acid reflux), which occurs when the stomach’s acidic contents flow back up to the esophagus.
• Gastroparesis: This is a disorder in which the nerves and muscles of the stomach are paralyzed, slowing down digestion.
• Pancreatitis: This is inflammation of the pancreas, the digestive organ behind your stomach. Excessive alcohol consumption, gallstones, medication side effects, or genetics can cause it.
• Hepatitis: This liver inflammation can result from a viral infection, alcohol abuse, poisoning, or an autoimmune disorder (in which the immune system attacks the liver).
• Peptic ulcer disease: Also known as a stomach or duodenal ulcer, this occurs when a sore develops in the lining of the stomach, leading to bleeding, holes, or blockage of the GI tract. 
• Gallstones (cholelithiasis): Gallstones are pebble-like deposits of bilirubin (a blood compound) or cholesterol in the gallbladder. If these stones block the bile ducts, bile (a digestive fluid) builds up, causing symptoms.
• Complicated GERD: GERD can lead to serious complications, such as Barrett’s esophagus (inflamed esophagus tissues), erosive esophagitis (ulcers or erosion in the esophagus), and esophageal structures (narrowed esophagus due to scarring and inflammation).
• Diverticular disease (diverticulosis): This occurs when hollow growths, or sacs, form in the colon’s lining.
• Hemorrhoids: These are veins or arteries near your anus or in your lower rectum that have become swollen or inflamed. They can be external growths or develop internally.
• Crohn’s disease: This is a type of inflammatory bowel disease (IBD) and can affect any part of the GI tract from the mouth to the anus.
• Ulcerative colitis: Another type of IBD, ulcerative colitis leads to inflammation that impacts the large intestine and colon.
• Colorectal cancer: Cancer of the colon or rectum starts as benign (non-cancerous) growths called polyps that can become cancerous.

The symptoms of gastrointestinal diseases vary in severity and can depend on your specific disease. Several GI diseases share similar symptoms, including:

• Abdominal pain and cramping, which can sometimes travel to the lower back
• Diarrhea, sometimes with blood
• Constipation (making fewer than three bowel movements a week)
• Fatigue
• Nausea or vomiting
• Chronic urges to pass stools, even after you’ve gone 
• Blood or pus in the stools
• Bloating
• Uncomfortable fullness after eating

Other signs you may have a gastrointestinal disease include:

• Regurgitation (stomach acids flowing back up), heartburn, or chest pain
• Burping
• Fever
• Difficulty swallowing, also known as dysphagia 
• Jaundice (a yellowing of the skin or eyes)
• Dark-colored urine that is brown or red
• Clay-colored stool
• Joint pain

Gastrointestinal diseases can be the result of many factors, including:

• Viral infection: Viruses are at the root of a range of GI diseases, including viral hepatitis and gastroenteritis (stomach flu). 
• Bacterial infection: Bacteria can affect the GI tract. Diarrhea can start due to Vibrio cholerae (cholera), Clostridioides difficile (C. diff), or Escherichia coli (E. coli) bacteria. 
• Parasitic infection: Parasites—amoebas or other microorganisms—can lead to GI diseases. Parasites include Giardia lamblia (a cause of chronic diarrhea), Entamoeba histolytica, and Cystoisospora belli. 
• Toxicity: Ingesting toxic substances or poisons can lead to GI diseases. These substances include lectins (in certain uncooked plants or beans), heavy metals, or other substances found in nature or food.
• Hernia: These are holes or weak spots in the walls of the tissues surrounding the abdomen. A cause of GERD is a hiatal hernia, which occurs when the stomach pushes through, impacting the esophagus. 
• Medication side effects: Nonsteroidal anti-inflammatory drugs (NSAIDs) like Motrin (ibuprofen), serotonin receptor agonists like Clozaril (clozapine), and anticancer medications can all affect GI health.
• Alcohol use: Excessive alcohol use can impact the health of the liver and pancreas, leading to certain types of hepatitis and pancreatitis. 
• Autoimmune disorders: Autoimmune disorders arise when your body’s immune system mistakenly attacks healthy cells. This can lead to conditions like gastritis, ulcerative colitis, and Crohn’s disease.
• Diet: Some GI diseases result from diet choices or food sensitivity. Excess fiber consumption can lead to diarrhea, and insufficient fluids can lead to constipation. Symptoms of celiac disease can begin if you eat gluten when allergic.

Risk Factors

Several health and lifestyle factors can raise your risk of developing a GI disease. Depending on the condition you have, these risk factors include:

• Specific genetics or a family history of GI disease
• A diet low in fiber
• Inadequate exercise or physical activity
• Excessive alcohol consumption
• Stress or anxiety
• Not going to the bathroom when you need to
• Overuse of anti-diarrheal medications
• Use of antacids made with calcium or aluminum
• Pregnancy
• Use of certain medications, including iron supplements, antidepressants, and opioid pain relievers
• Being overweight or having obesity
• Meal consumption within three hours of going to bed

The first step in diagnosing GI diseases involves assessing your symptoms, medical history, family history of disease, and medication list. A healthcare provider will likely perform a physical exam, such as pressing on your stomach. 

Diagnosis may also involve the following tests:

• Blood tests: Measuring certain factors using a blood sample helps providers detect chemical biomarkers of inflammation, infection, cancer, or other diseases of the pancreas, liver, or gallbladder.
• Fecal exam: Samples of stools can be tested for disease markers, making this a standard for diagnosing a wide range of GI diseases.
• Colonoscopy: To screen for polyps, cancer, or inflammation in the colon or rectum, healthcare providers use a specialized camera on an adjustable tube (colonoscope). They may also collect a tissue sample for testing (biopsy).
• Endoscopy: Healthcare providers pass an endoscope—a type of camera with a light on an adjustable tube—through the mouth or anus to assess tissues or collect a sample for biopsy. 
• Imaging: Ultrasound, X-ray, computerized tomography (CT), and magnetic resonance imaging (MRI) can give providers a different look at your insides. Another method, cholescintigraphy, relies on a radioactive dye to detect gallstones in bile ducts. 

Healthcare providers’ approach to treating gastrointestinal diseases depends on the specific disease and its cause.

Medications

Prescribed and over-the-counter (OTC) medications can be central to treating GI diseases. Medications for GI diseases include:

• Proton pump inhibitors (PPIs), such as Prevacid (lansoprazole) or Prilosec (omeprazole), which reduce stomach acid
• Histamine receptor antagonists (H2 blockers) like Pepcid AC (famotidine) or Tagamet (cimetidine), which reduce stomach acid
• Antacids like calcium carbonate (sold under brand names like Tums and Rolaids)
• Antibiotics like Zithromax (azithromycin) or Vibramycin (doxycycline) 
• Anti-diarrheal medications, such as Imodium (loperamide) or Viberzi (eluxadoline)
• Laxatives like lubiprostone (sold under brand names like Metamucil and Amitiza)
• Antiemetic (anti-nausea) drugs, such as Phenadoz (promethazine) or Bismuth (bismuth subsalicylate)
• Aminosalicylates like mesalamine (sold under brand names like Delzicol and Rowasa), which can manage inflammation in IBD
• Certain antidepressants like Remeron (mirtazapine), which may help with symptoms like nausea and vomiting 

Dietary Changes

Alongside other treatments, adjusting your diet can help ease symptoms of GI diseases and prevent disease flares (times of disease activity). Healthcare providers may recommend you do the following: 

• Increase fiber intake and avoid gluten for conditions like IBS and diverticulosis
• Follow a low-FODMAP diet, which restricts and gradually reintroduces certain carbohydrates that can impact IBS symptoms
• Stick to soft or liquid food diets in cases where digestion or swallowing is difficult
• Limit caffeine and alcohol, which can impact GI health

Therapy

Mental health conditions can make GI symptoms worse. As such, mental health therapies, such as cognitive behavioral therapy (CBT) or psychotherapy, can become a part of treatment. Hypnotherapy (using techniques to stimulate a relaxed state) and mindfulness techniques (meditation and deep breathing) may also help ease anxiety and improve outcomes.

Surgery

Surgery is typically the last resort for gastrointestinal diseases. Surgery is typically recommended when other treatments don’t work or if the underlying cause of symptoms requires repair, as in a hiatal hernia. 

Surgical procedures for GI diseases can include:

• Hernia repair: Surgery can repair a hiatal hernia, closing the abdominal wall and treating any associated GERD.
• Fundoplication: Using a minimally invasive approach, the surgeon takes the upper part of the stomach (fundus) and wraps it around the lower part of the esophagus to prevent GERD-related heartburn.
• Resection: For cancer and certain other cases, resection involves removing all or part of the stomach (gastrectomy) or esophagus (esophagectomy). For severe cases of diverticulosis, cancer, and other inflammatory conditions, the surgeon removes all or part of your colon during a colon resection.
• Weight loss surgery: Since excess weight can impact a range of GI diseases, surgeries promoting weight loss, like gastric bypass, can be a part of treatment.
• Jejunostomy: For gastroparesis, a hole in the abdomen is created to insert a feeding tube that goes straight to the small intestine.

Healthcare providers may also perform surgery to remove hemorrhoids, tumors, or other growths along the GI tract.

For preventable gastrointestinal conditions, prevention primarily consists of making lifestyle changes that support digestion. Common approaches include:

• Ensure you’re eating a healthy, well-rounded diet or a diet recommended for your condition
• Improve sleep, and if you’re an adult, make sure you’re getting at least 7-8 hours a night
• Get enough physical activity, aiming for at least 150 minutes of light to moderate activity weekly
• Get screened for colorectal cancer, and visit a healthcare provider if you notice any concerning symptoms
• Avoid heavy meals within three hours of bedtime
• Take part in meditation or relaxing activities 

Gastrointestinal (GI) diseases are conditions affecting your digestive system. There are many types of GI diseases and two main categories: functional and structural. Functional GI diseases, such as IBS and GERD, are conditions where your digestive system doesn’t work properly due to miscommunication between your brain and gut. Structural GI diseases, such as IBD and hemorrhoids, are conditions where your digestive tract has physical issues.

Gastrointestinal diseases cause a wide range of symptoms, including heartburn, constipation, diarrhea, and abdominal pain. Treatment depends on the disease and its underlying cause and may include dietary changes, medication, or surgery.