Ulcers are defined as the loss of a superficial section of tissue, usually affecting the mucous membranes
lining certain organs, particularly of the digestive system, or found on the skin, in which case they form lesions. Peptic ulcers
develop on the mucous
membrane lining the stomach or duodenum, the first section of the small intestine. They are qualified as ulcers once the loss of tissue progresses to affect
the layer of muscular tissue below the mucosa. Peptic ulcers are caused by certain factors, including acidic imbalance in the stomach and the body's mechanisms to fight it, aspirin or other anti-inflammatory drugs
, or a bacterial infestation of Helicobacter pylori, which also causes chronic gastritis
. Bleeding observed in the digestive tract is indicative of an ulcer, which can sometimes progress to a gastric or duodenal perforation.