Burning or gnawing pain in the upper abdomen
Pain that comes and goes, often worse when the stomach is empty
Pain that may improve or worsen after eating
Nausea or vomiting
Bloating or feeling full quickly
Loss of appetite
Frequent burping or belching
Heartburn or indigestion
Dark, black, or tarry stools
Vomit that looks like blood or coffee grounds
Unexplained weight loss
Fatigue or weakness
Severe sudden abdominal pain
Dizziness or fainting
Symptoms lasting more than a few days or returning often