Noting that loss of control is a major concern confronting patients experiencing an illness, this paper critically analyzes the research literature on control and clarifies the implications of this research for provider-patient communication. The paper first defines control, noting that the most frequently cited definition is the "locus of control" perspective, which categorizes perceptions of control as internal or external. The paper then examines what patients are likely to want to control, such as environment, treatment, and relationships with care providers. The reasons control is important for patients are then discussed, followed by descriptions of three conceptualizations of control and how they apply to the patient-provider relationship. The first concerns locus of control research, which examines whether patients believe they are responsible for their illness, or attribute it to outside forces. The behavior perspective is then addressed, which looks at how patients respond to their situations, followed by a discussion of the relational control perspective, which looks at control as a process. A summary notes that further research is needed on ways these perspectives contribute to an understanding of control in provider-patient communication. Five pages of references are included. (JC)