*What is an Ulcer?* An ulcer is a sore or open wound that develops on the skin or mucous membrane due to the breakdown of tissues. Most commonly, ulcers occur in the digestive tract. *Types of Ulcers* *Peptic Ulcers* : Sores in the lining of the stomach or duodenum (small intestine). *Gastric ulcer* – in the stomach. *Duodenal ulcer* – in the small intestine. *Esophageal Ulcer* : In the esophagus. *Mouth Ulcer* : Inside the lips, cheeks, or on the tongue. *Venous Ulcer* : On the legs, due to poor blood flow. *Genital Ulcer* : On the genital area due to infections like herpes or syphilis.