In some individuals habitual cheek and lip biting becomes a fixed neurosis. Pieces of oral mucosa are actually torn free from the surface, producing a distinctive clinical appearance termed morsicatio buccarum et labiorum. Sometimes it may be confused with other dermatological disorders involving the oral mucosa, and can lead to misdiagnosis. Most patients with this condition are unaware of their habit and will not aid in the diagnosis. We suggest that the histopathological features of this condition are distinctive, if not pathognomonic, and that an accurate diagnosis should be rendered if a biopsy sample is taken. Two cases are reported herein that were originally misdiagnosed as pemphigus, one of which resulted in complications of improper oral corticosteroid use.