Closely associated with chronic duodenal ulcer is duodenitis, a chronic inflammation of the duodenum without ulceration. Duodenal ulcers are either indurated or non-indurated. But the clinical features of a chronic peptic ulcer may be traced to either a true ulcer or a submucous lesion which shows no stippling of the mucosa, and is not palpable. The latter type may be mistaken for a healed ulcer, may cause gastric or intestinal hemorrhage, and may become adherent to the gall bladder or other organs. The microscopic features are no abrasion of the mucosa, and lymphatic infiltration of the submucosa and muscularis. In 26 cases of duodenitis, the sex incidence is about equal. Average [male] age is 39, [female] 45. The average length of symptoms is 11 yrs. In duodenal ulcer, gastritis and duodenitis occur. Diagnosis and treatment are discussed. Extensive bibliography.