The social work component of this study was conducted for ethical reasons to monitor the impact on relatives of providing therapy to severely brain-injured patients on an innovative rehabilitation treatment program in an acute care hospital. The authors identify stressors experienced by the family caregivers. Findings are based on 450 interviews conducted by three research social workers during the 18-month study period with 78 family caregivers of the 37 patients. The results indicate that involvement in providing treatment was stressful, because of both the demands on the family and the unproven efficacy of the treatment. The authors recommend that a family's ability to provide treatment be clearly assessed before recruitment and that relatives' stress be monitored during their involvement. The findings emphasize the important role social workers can perform in identifying and monitoring such stress.