Black tongue associated with linezolid

Darkening of the tongue and oral mucosa is a reaction pattern that can be related to a number of physiologic, metabolic, and toxic disorders, and medications and exogenous substances. Black discoloration of the tongue should be distinguished from black "hairy" tongue, which is characterized by hypertrophy of the filiform papillae. We report a case of a 42-year-old man presented with a black discoloration of his tongue during treatment with linezolid for spondylodiscitis. So in conclusion, tongue discoloration is a benign and reversible condition and a probable adverse event associated with linezolid. We present this case to increase clinicians' awareness of a new potential adverse effect of linezolid.