It is essential for laryngologists, speech and language pathologists, and others caring for professional voice users to be familiar with the potential vocal effects of any substance ingested by a professional voice patient. This article reviews pharmacologic agents that may have laryngeal side effects. Essentially, any ingested substance is suspect as a cause for voice dysfunction. It is also necessary for laryngologists to educate voice professionals about the consequences of drugs on the voice and the potential problems associated with properly prescribed medication.