Chronic ulcerative stomatitis (CUS) is a rare mucocutaneous disease. It is characterized by the presence of chronic painful oral erosive or ulcerative lesions with relapses. The most commonly affected areas are the tongue, buccal mucosa and the gingiva. A diagnosis of CUS is made based on the characteristic direct immunofluorescence findings – the presence of IgG antibodies bound to nuclei of keratinocytes of the basal and parabasal cell layers, with the unique stratified epithelial specific-antinuclear antibody (SES-ANA) pattern. Indirect immunofluorescence, with monkey and guinea pig oesophagus as substrates, is used to confirm the diagnosis. In the treatment of CUS, hydroxychloroquine alone or with small doses of corticosteroids is found to be the drug of choice in limiting the disease.