In this article we describe the background, design, and preliminary results of a medications module within Patient Gateway (PG), a patient portal linked to an electronic health record (EHR). The medications module is designed to improve the accuracy of medication lists within the EHR, reduce adverse drug events and improve patient-provider communication regarding medications and allergies in several primary care practices within a large integrated healthcare delivery network. This module allows patients to view and modify the list of medications and allergies from the EHR, report non-adherence, side effects and other medication-related problems and easily communicate this information to providers, who can verify the information and update the EHR as needed. Usage and satisfaction data indicate that patients found the module easy to use, felt that it led to their providers having more accurate information about them and enabled them to feel more prepared for their forthcoming visits. Further analyses will determine the effects of this module on important medication-related outcomes and identify further enhancements needed to improve on this approach.