A challenge in individual and public health at the start of the 21st century is to effectively communicate health and science information about disease and complex emergencies. The low health literacy of millions of adults in the USA has been referred to as a 'silent killer'. A popular approach to improving health communication and health promotion to low health literate consumers has been to simplify the language of health information. The expected result has been that individuals and groups will better understand information and will then make informed decisions about their health and behaviors. This expectation has grown to include the belief that the public will be better prepared to take appropriate action in complex natural and man-made emergencies. Demonstrating the efficacy of this approach remains, in large part, uninvestigated. And it is becoming more evident that health literacy itself is complex and multifaceted. This article applies linguistic and sociolinguistic models in order to better articulate the role of simplification in health communication and health promotion. Focusing on two models from sociolinguistics-pragmatics and text theory-the article discusses their usefulness in rethinking message simplification. The discussion proposes that a richer, more theory-based understanding of text structures and functions, along with other powerful constructs, including cultural appropriateness, relevancy and context, are needed to close the gaps between health messages, health messengers and patients/the public. The article concludes by making recommendations for future study to empirically test the strengths and limitations of these models and constructs.