By its very definition, efficacy’s meanings remain fluid, their particularities contingent on context. The change seen as significant may occur on a symbolic level or through the removal of physical symptoms. It may address conditions of a social body. Some discussions differentiate between “healing” and “curing.” Many of these meanings surface when examining what efficacy means in the practice of acupuncture in the United States. This complex phenomenon is possible largely because acupuncture draws on the qi paradigm on the one hand, allowing for the most ephemeral dimensions of experience to be included in considerations of efficacy. On the other hand, in the most material sense, acupuncture is also susceptible to being conceptualized as a device, independent of that same paradigm, allowing for the insertion of biomedical models and criteria. Pluralism within acupuncture itself intersects with, and even embodies, the medical pluralism of U.S. culture.