Patients with inadequate health literacy have a complex array of communications difficulties, which may interact to influence health outcome. These patients report worse health status and have less understanding about their medical conditions and treatment. Preliminary studies indicate inadequate health literacy may increase the risk of hospitalization. Professional and public awareness of the health literacy issue must be increased, beginning with education of medical students and physicians and improved patient-physician communication skills. Future research should focus on optimal methods of screening patients to identify those with poor health literacy, effective health education techniques, outcomes and costs associated with poor health literacy, and the causal pathway of how poor health literacy influences health.