Explanations designed to teach, rather than to support scientific claims in scholarly works, are essential in health and risk communication. Patients explain why they think their symptoms warrant medical attention. Clinicians elicit information from patients and explain diagnoses and treatments. Families and friends explain health and risk concerns to one another. In addition, there are websites, brochures, fact sheets, museum exhibits, health fairs, and news stories explaining health and risk to lay audiences. Unfortunately, research on this important discursive goal is less extensive than is research on persuasion, that is, efforts to gain agreement. One problem is that explanation-as-teaching has not been carefully conceptualized. Some confuse this communication goal and discursive type with its frequent verbal and visual features, such as simple wording or diagrams. Others believe explanation-as-teaching does not exist as a distinctive communication goal, maintaining that all communication is solely persuasive: that is, designed to gain agreement. Explanation-as-teaching is a distinct and important health communication goal. Patient involvement in decision making requires that both clinicians and patients understand options underlying health-care choices. To explore types of explanation-as-teaching, research provides (a) several ways of categorizing health and risk explanations for lay audiences; (b) evidence that certain textual and graphic features overcome predictable confusions, and (c) illustrations of each explanation type. Additionally, explanation types succeed or fail in part because of the social or emotional conditions in which they are presented so it is important to note research on conditions that support patients, families, and clinicians in benefiting from explanations of health and risk complexities and curricula designed to enhance clinicians’ explanatory skill.