Bullous diseases of the oral cavity cause painful, erosive lesions. These must be distinguished from aphthous ulcers and vesicles with which they are often confused. The causes of post-bullous erosions are varied. Acute lesions can be due to trauma, erythema multiforme or toxidermia. The examination of the skin and the medical history are the keys to diagnosis. Chronic bullous diseases can be due to congenital diseases (epidermolysis bullosa or lymphangioma), which are easily evoked by the age at which the symptoms appear and the clinical picture. Acquired chronic bullous diseases include lichen planus and bullous auto-immune diseases. The keys to diagnosis are the presence of other mucosal or cutaneous lesions, the histological examination and the finding of perilesional antibodies on the mucosa. The symptomatic treatment of oral bullous lesions includes the following of a specific diet, use of antalegics and the prevention or treatment of superimposed infection.