Medical rehabilitation in Germany has a long tradition. It is covered by the statutory sickness funds and pension schemes, and is aimed at the prevention of work disability and need for nursing care due to chronic conditions. Chronically ill but health-literate patients - patients capable of making good health-related decisions, or of participating strongly in this decision making - have better health outcomes. To enhance health literacy and participation, medical rehabilitation relies heavily on patient education. This article describes health literacy from the perspective of educational research, outlines the basics of learning principles, and draws conclusions for developing patient education programmes in medical rehabilitation. Implementing a constructivist learning paradigm promotes changes within the trainer team and within the rehabilitation institution - turning it into a health-literate health care organisation. Health literacy in medical rehabilitation is aimed at neither turning the patient into a physician nor replacing evidence-based recommendations through subjective preferences. Medical rehabilitation reaches patients best by using modern health education programmes based on findings from education research, theoretically founded and directed towards building competencies. Furthermore, an educationally qualified training team and a rehabilitation institution are essential in enabling formal and informal learning processes.