Signs and symptoms
Symptoms
Patients experiencing indigestion likely report one, a combination of, or all of the following symptoms:
upper abdominal pain or discomfort
bloating
early satiety
postprandial fullness
nausea with or without vomiting
anorexia
regurgitation
belching

Signs
There may be abdominal tenderness, but this finding is nonspecific and is not required to make a diagnosis. However, there are physical exam signs that may point to a different diagnosis and underlying cause for a patients reported discomfort. A positive Carnett sign (focal tenderness that increases with abdominal wall contraction and palpation) suggests an etiology involving the abdominal wall musculature. Cutaneous dermatomal distribution of pain may suggest a thoracic polyradiculopathy. Tenderness to palpation over the right upper quadrant, or Murphys sign, may suggest cholecystitis or gallbladder inflammation. Alarm symptoms
Also known as Alarm features, alert features, red flags, or warning signs in gastrointestinal (GI) literature. Alarm features are thought to be associated with serious gastroenterologic disease and include:
chronic gastrointestinal bleeding
progressive unintentional weight loss
progressive difficulty swallowing (dysphagia)
persistent vomiting
Iron deficiency anemia
Vitamin B12 deficiency (Pernicious anemia)
epigastric mass

Cause
Indigestion is a diagnosis related to a combination of symptoms that can be attributed to "organic" or "functional" causes. Organic dyspepsia should have pathological findings upon endoscopy, like an ulcer in the stomach lining in peptic ulcer disease. Functional dyspepsia is unlikely to be detected on endoscopy but can be broken down into two subtypes, epigastric pain syndrome (EPS) and post-prandial distress syndrome (PDS). In addition, indigestion could be caused by medications, food, or other disease processes. Psychosomatic and cognitive factors are important in the evaluation of people with chronic dyspepsia.
Functional Dyspepsia
Functional dyspepsia is a common cause of chronic heartburn. More than 70% of people have no obvious organic cause for their symptoms after evaluation. Symptoms may arise from a complex interaction of increased visceral afferent sensitivity, gastric delayed emptying (gastroparesis) or impaired accommodation to food. Diagnostic criteria for functional dyspepsia categorize it into two subtypes by symptom: epigastric pain syndrome and post-prandial distress syndrome. Anxiety is also associated with functional dyspepsia. In some people, it appears before the onset of gut symptoms; in other cases, anxiety develops after onset of the disorder, which suggests that a gut-driven brain disorder may be a possible cause. Although benign, these symptoms may be chronic and difficult to treat. Epigastric Pain Syndrome (EPS)
Defined by stomach pain and/or burning that interferes with daily life, without any evidence of organic disease. Post-Prandial Distress Syndrome (PDS)
Defined by post-prandial fullness or early satiation that interferes with daily life, without any evidence of organic disease. Food, herb, or drug intolerance
Acute, self-limited dyspepsia may be caused by overeating, eating too quickly, eating high-fat foods, eating during stressful situations, or drinking too much alcohol or coffee.