: Ulcers are sores on the mucous membranes of the alimentary canal and on the skin . Ulcers are commonly referred to as gastric ulcers or duodenal ulcers of the small intestine, commonly known as peptic ulcers . Although stomach hydrochloric acid and pepsin have so far been blamed for peptic ulcers, it is now certain that bacterial infection called Helicobacter pylori is one of the causes of duodenal ulcers. High levels of acid in the stomach are conducive to the transmission of these microorganisms. This is why proton pump inhibitors (PPIs ) are now being used to treat duodenal ulcers with antibiotics and hydrochloric acid . Stomach and duodenal ulcers can also be caused by painkillers and steroid medications. Long-term stomach ulcers are more likely to turn into cancer. Haematemesis , melaena, stenosis, and perforation of the duodenum are serious complications of duodenal ulcers that can lead to death. Ulcers in the colon are seen in a disease called ulcerative colitis . The sores on the back skin of patients who have been bedridden for a long time due to stress are commonly known as bed sores and decubitus ulcers in medicine . Diabetic ulcers are a long-term treatment for leprosy and other neurological disorders, as well as trophic ulcers and diabetic patients with high blood sugar , low blood supply , and peripheral neuropathy . The mucous membrane of the tongue and mouth cavity is characterized by an acute lesion called aphthous ulcer . Although the cause is not known, one type of virus is blamed. Aphthous ulcers heal spontaneously in a couple of weeks, but it is seen to be recurrent. Banglapedia.