There are many possible causes of indigestion. They include:

• Foods and beverages. Certain types of foods, such as spicy, greasy or fatty foods, can lead to indigestion. Alcoholic, caffeinated or carbonated beverages may also contribute to indigestion. It can also be caused by eating too quickly or eating too much. Swallowing excessive air while eating can also cause indigestion.
  
  
• Food intolerances or allergies. People with intolerances to certain substances, such as lactose in dairy products or gluten in grains, may experience indigestion after consuming these products.
  
  
• Smoking. Tobacco smoking may cause indigestion.
  
  
• Medications. Certain types of medications, such as antibiotics and nonsteroidal anti-inflammatory drugs (NSAIDs) can irritate the stomach and cause indigestion.
  
  
• Gastrointestinal (GI) disorders. Many disorders that affect the GI tract cause indigestion, including:
  
  
• • Gastritis. Inflammation or irritation of the stomach lining. Both acute (short-term) and chronic (long-term) gastritis can cause indigestion.
    
    
  • Peptic ulcer. An open sore, or ulcer, in the lining of the esophagus, stomach or duodenum.
    
    

    

  • Infection. Stomach infections caused by the microorganism Helicobacter pylori (H. pylori) can sometimes lead to gastritis or ulcers, both of which may lead to indigestion.
    
    
  • Gastroesophageal reflux disease (GERD). A backflow of acid from the stomach into the esophagus.
    
    

    

  • Motility disorders. People who experience delayed emptying of the stomach after eating frequently experience indigestion.
    
    
  • Pancreatitis. Inflammation or irritation of the pancreas, often due to gallstones or alcohol abuse.
    
    

    

  • Gallstones. Hard, stone-like concretions formed from substances in bile such as cholesterol or bilirubin that develop in the gallbladder or bile ducts.
    
    

    

  • Cholecystitis. Inflammation of the gallbladder that causes episodes of severe abdominal pain.
    
    
  • Cancer. Certain types of gastrointestinal cancer, including esophageal cancer and pancreatic cancer, may cause indigestion.
    
    
• Systemic conditions. Certain conditions, such as pregnancy or kidney failure, can cause indigestion.
  
  
• Anxiety or emotional trauma. These are possible causes of indigestion.
  
  
• Unidentifiable factors. The cause of some indigestion is unknown. This is called functional (nonulcer) dyspepsia.