Non-infectious ulcerative oral mucous membrane diseases are difficult to separate at first glance: they can appear as aphthous, bullous, lichenoid, drug-induced or toxic-irritative reactions. The overall considerations of history, localization of lesions, clinical and histological features, as well as direct and indirect immunofluorescence examination are required for the correct diagnosis. Some disorders start preferably at the oral mucosa, like pemphigus vulgaris and Adamantiades-Behçet disease, while others, such as cicatricial pemphigoid and habitual aphthosis generally are confined to the mucous membranes. This overview summarizes clinical and diagnostic features, differential diagnoses and current therapeutic possibilities of non-infectious inflammatory stomatopathies, which possess a specific position among skin diseases in distinction to infectious or neoplastic oral ulcers. This group of diseases includes aphthous lesions, lichen planus mucosae, lupus erythematosus, disorders with intraepidermal or subepidermal formation of blisters including pemphigus, bullous pemphigoid, erythema multiforme and variants as well as allergic or toxic contact stomatitis.