Trismus is a condition that impairs eating, interferes with oral hygiene, restricts access for dental procedures, and may adversely affect speech and facial appearance. The success of treatment depends on recognition of the cause and initiation of appropriate management. Ideally, trismus appliances are used in conjunction with physical therapy and are most effective when the condition is the result of muscle fibrosis or scar tissue that has not yet matured. Trismus appliances act either externally or internally, and the forces they impart can be continuous or intermittent, light or heavy, and elastic or inelastic. Six appliances have been described in the literature. A seventh appliance, a plastic tapered cylinder, is also effective. The tapered cylinder relies on the patient's depressor muscles to separate the jaws, and allows easy appreciation of the progress made. The stretching force applied with this appliance is limited by the strength of the patient's depressor muscles.