Masanori Masui

1 Introduction Black hairy tongue is a benign lesion characterized by a black to brown, hair-like appearance on the dorsum of the tongue caused by hypertrophy, elongation, and defective desquamation of the filiform papillae. It is usually seen in adults and has been associated with poor oral hygiene, antibiotic or steroid use, xerostomia, smoking, and poor general condition [1]. Among these predisposing factors, medication exposure deserves particular attention when evaluating black hairy tongue.