We report on the results of an ethnographic study of how elders manage their medication with the objective of informing the design of in-home assistive health technology to support “medication adherence.” We describe the methods by which elders organize and remember to take their medication—methods that leverage a kind of distributed cognition. Elders devise medication management systems that rely on the spatial features of their homes, the temporal rhythms of their days, as well as the routines that occasion these places and times to help recall and prospective remembering. We show how mobile health care workers participate in the development and execution of these systems, and “read” them to infer an elder’s state of health and ability to manage medication. From this analysis, we present five principles for the design of assistive technology that support the enhanced but on-going use of personalized medication management systems, and that also allow for remote health car...