Social work in health originated in almshouses and hospitals in the late 19th century to assess patients' eligibility for free treatment and mobilize resources. Over time, the role has expanded from gatekeeping to include assessment, support, advocacy, and connecting patients to community resources. The medical model historically situated social workers in a subordinate role to doctors, focusing on discharge planning. However, models emphasizing chronic care and biopsychosocial factors now promote multidisciplinary, preventative approaches and greater collaboration between social workers and other health professionals. Today social workers in health settings provide services ranging from individual casework to community development and policy work.