This paper reviews the definitions of complementary and alternative medicine (CAM) and adopts the definition, "Complementary and alternative medicine is defined through a social process as those practices that do not form part of the dominant system for managing health and disease" (Jonas, 1996, p.1). The authors review the literature on CAM usage in the general and HIV/AIDS populations, and the impact of CAM on modern Western medicine and the allied health professions. Host-virus factors in HIV/AIDS are examined from the perspectives of both Western medicine and complementary and alternative medicine. Methodological issues and the historical argument over the relative importance of host and microbe are explored in relation to HIV/AIDS and the CAM and Western approaches to HIV/AIDS care.