"The degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate
health decisions."

The National Network of Libraries of Medicine expands on the topic: "Health literacy includes the ability to understand instructions on prescription drug bottles, appointment slips, medical education brochures, doctor's directions and consent forms, and the ability to negotiate complex health care systems.

Health literacy is not simply the ability to read. It requires a complex group of reading, listening, analytical, and decision-making skills, and the ability to apply these skills to health situations. 

Health literacy varies by context, and is not necessarily related to years of education or general reading ability. A person who functions adequately at home or work may have marginal or inadequate literacy in a health care environment.

With the move towards a more "consumer-centric" health care system as part of an overall effort to improve the quality of health care and to reduce health care costs, individuals need to take an even more active role in health care-related decisions. A high rate of health literacy can help the public accomplish this."

The U.S. Department of Health and Human Services identifies improved health literacy as a primary objective of the Healthy People 2020 program. The second objective is to "increase the proportion of persons who report that their healthcare providers have satisfactory communication skills". Healthy People 2020 identified health literacy as an important component of patient compliance and medical decision-making between patients and healthcare providers. Health communication strategies for clinicians can help improve population health outcomes and health care quality.

The Healthy People 2020 objectives page explains that “all people have some ability to manage their health and the health of those they care for. However, with the increasing complexity of health information and health care settings, most people need additional information, skills, and supportive relationships to meet their health needs.” 

Both health care providers and patients play important roles in health literacy.

There are many ways improved health communication can have a positive impact on health, health care, and health equity:

• Improve health care quality and safety.
• Increase the efficiency of health care and public health service delivery.
• Improve the public health information infrastructure.
• Support care in the community and at home.
• Facilitate clinical and consumer decision-making.
• Build health skills and knowledge.