Sales of over-the-counter (OTC) tooth-whitening products have increased sharply in recent years because of heightened consumer demand for esthetic care, success of in-office and professional home bleaching systems, and heavy promotion by product manufacturers. All the whitening products contain hydrogen peroxide or carbamide peroxide and differ in their mode of delivery. Because tooth whiteners are not regulated by the Food and Drug Administration, many retail products have not undergone rigorous, objective, clinical testing and hence may be of questionable efficacy and safety. OTC tray-based systems in particular must be used with caution because ill-fitting trays can lead to soft-tissue injury, malocclusion problems, and poor compliance. Non--tray-based systems, including a paint-on system and whitening strips, have recently become available. These products are inexpensive, convenient, and easy to use, and they represent the fastest growing segment of the retail market. Whitening dentifrices comprise approximately 50% of OTC tooth whitening products work mainly by abrasion to remove superficial stains. With heightened consumer interest in whiter teeth, clinicians must become familiar with OTC products to provide optimal solutions and treatment to patients.