Stomach bloating may refer to a sensation of fullness or pressure, typically after eating, and/or excessive gas accumulation within the gastrointestinal tract. Typically these symptoms are associated with indigestion, however, there are various other causes that may or may not be related to the gastrointestinal tract (gut).

With stomach bloating, there may be little or no enlargement of the abdomen (distension). Common causes of a visible bulging or protrusion of the stomach may be due to fluid (ascites), feces (constipation), fat (abdominal fat/central obesity), fetus (pregnancy), flatus (gas accumulation). This is is discussed further under :

Sensation of Fullness

A feeling of fullness or pressure in the stomach, abdominal area or under the left ribcage, is often described as stomach bloating especially if it follows eating or drinking. This sensation may be a result of gas accumulation (described below) or a vague stomach or abdominal discomfort (stomach ache). It may be accompanied by nausea and vomiting.

The causes of this sensation of fullness or pressure in the stomach includes :

  • Functional dyspepsia (non-ulcer dyspepsia)
    • This is a syndrome of symptoms that typically start after eating when there is no diagnostic evidence of any other gastrointestinal disease.
  • Gastritis
    • Inflammation of the lining of the stomach commonly due to H.pylori infection or use of NSAIDs. It can progress to a peptic ulcer.
  • Peptic ulcer
    • Ulceration in the lining of the esophagus, stomach or duodenum usually as a result of chronic gastritis.
  • Gastroenteritis
    • Infection of the stomach and duodenum causing nausea, vomiting, diarrhea and a fever.
  • Hiatal hernia
    • Protrusion of a portion of the stomach into the chest cavity through the diaphragmatic opening.
  • Gastric outlet obstruction
  • Irritable bowel syndrome
    • Functional bowel disorder that may affect gut motility and characterized by non-specific symptoms like a sensation of bloating. Excessive gas may also be contribute to stomach bloating.
  • Surgery
    • Post-operative inflammation of the stomach may cause a sensation of fullness. This feeling may be chronic in surgical resection (removal of a part of the stomach in the treatment of conditions like cancer) or bariatric (weight loss) surgery.

Gas Accumulation

The build up of gas in the gut may be due to a number of  factors that are not related to any disease process (physiological, non-pathological).

  1. Air swallowing (aerophagia)
  2. Carbonated beverages
  3. Gassy foods
  4. Chemical digestion
  5. Normal intestinal flora (gut bacteria)

If one or more of these causative factors are disrupted, the gas accumulation within the gut can increase substantially.  The causes that may increase gas in the upper gut includes :

  • H.pylori infection
    • Infects the stomach and duodenum, increases gastric acid secretion and causes gastritis.
  • Small intestine bacterial overgrowth
    • Overgrowth of intestinal bacteria like Clostridium difficile increases consumption of food in the gut thereby producing gas.
  • Food intolerance and malabsorption
    • Intolerances to foods high in lactose (dairy) and gluten (wheat) and malabsorption of sugars likes fructose and sorbitol.
  • Gastroparesis
  • Pancreatic exocrine insufficiency
  • Biliary Stasis
    • Reduced secretion of bile due to diminished production or obstruction in the bile duct (gallstones or tumor).


Article reviewed by Dr. Greg. Last updated on November 30, 2010