Self-injurious behavior (SIB) is a serious health hazard, especially among individuals with severe and profound mental retardation, sometimes leading to drastic therapeutic measures. Environments in which there are long periods with minimal opportunities for constructive activity are conducive to the development of SIB, but even highly motivated, hard-working caregivers sometimes have difficulty providing sufficient personal interactions to prevent it. In this case study, one person's self-injurious hand mouthing was significantly reduced by analyzing her toy play and consistently providing her with preferred toys. The results showed that careful and consistent attention to assuring that preferred materials are available for self-entertainment may be an effective and efficient method for managing some cases of SIB during times when other activities and treatments are unavailable.It has been estimated that 7-16% of individuals with severe or profound mental retardation engage in hand mouthing to the extent that it becomes a treatment objective (Rast & Jack, 1992). Hand mouthing can result in red, swollen, calloused hands, sometimes with lesions that become infected. The behavior can be problematic because it can: (1) cause tissue damage, leading to infection and (in rare cases) loss of digits; (2) interfere with productive manual activities; and (3) interfere with social relationships and integration, due to the repugnant sight and smell it produces.In a recent summary of state of the art diagnosis and treatment for selfinjurious mouthing, Rast and Jack (1992) identified several problems with existing treatments. Developing an effective treatment is often difficult, sometimes requiring weeks of experimentation with various procedures and treatment parameters. Furthermore, treatments are often so labor intensive thatThe authors would like to acknowledge the assistance of Jeanne Lyle for assistance with reliability observations. A special thanks to Dr. J. Iverson Riddle for his continuing support of research at Western Carolina Center. Requests for reprints can be obtained by writing the first author at