Methamphetamine is not a new drug. It has a long and storied history of legitimate clinical use and recreational abuse. Unfortunately, abuse of methamphetamine is increasing with alarming frequency in the United States and leads to appalling destruction of dentition. The pathognomonic effects of methamphetamine abuse on teeth have led to the term "meth mouth." This term, while descriptive of the clinical appearance of patients, is a misnomer. A review of available information on methamphetamine abuse is presented and discussed. A clinical case is documented to help clinicians recognize and manage patients who may be abusing methamphetamines. Palabras clave: crystal meth, dental caries, dentistry, drug abuse, local anesthesia, meth mouth, methamphetamine