Patient materials are often written above the reading level of most adults. Tool 11 of the Health Literacy Universal Precautions Toolkit ("Design Easy-to-Read Material") provides guidance on ensuring that written patient materials are easy to understand. As part of a pragmatic demonstration of the Toolkit, we examined how four primary care practices implemented Tool 11 and whether written materials improved as a result. We conducted interviews to learn about practices' implementation activities and assessed the readability, understandability, and actionability of patient education materials collected during pre- and postimplementation site visits. Interview data indicated that practices followed many action steps recommended in Tool 11, including training staff, assessing readability, and developing or revising materials, typically focusing on brief documents such as patient letters and information sheets. Many of the revised and newly developed documents had reading levels appropriate for most patients and--in the case of revised documents--better readability than the original materials. In contrast, the readability, understandability, and actionability of lengthier patient education materials were poor and did not improve over the 6-month implementation period. Findings guided revisions to Tool 11 and highlighted the importance of engaging multiple stakeholders in improving the quality of patient materials.