Common causes of bleeding in the stomach include abdominal and intestinal ulcers, cancer and gastritis, states WebMD. Excessive consumption of alcohol, which can trigger an inflammatory response in the stomach lining, is also known to cause gastric bleeding.
The stomach is a major digestive organ that forms part of the gastrointestinal tract, which also include the small and large intestines, mouth and esophagus. Bleeding that originates from any of these organs is typically a manifestation of an underlying medical condition. Hemorrhaging in the stomach may be acute, which is sudden and significant, or it can be chronic, which is prolonged and less severe.
Peptic ulcers are open wounds in the stomach lining that cause erosion of the mucous membrane, which eventually leads to bleeding. The formation of these sores is generally attributed to a bacterial infection and extended use of non-steroidal anti-inflammatory drugs, explains the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health. People who undergo invasive procedures and those who sustain head injuries and burns may also develop stress-associated ulcers.
Untreated gastritis is also one of the leading causes of abdominal bleeding. This condition occurs due to injuries, infections, Crohn's disease, severe health problems and as a side-effect to medication usage. Benign and malignant growths may also cause the stomach to bleed, which is directly related to a patient's weakening digestive tract.