The Institute of Medicine has described the need for comparing models of care delivery involving complementary health approaches and conventional medical practitioners. As a step toward addressing this need, we used a nationally representative 11-year sample of office-based visits to physicians from the National Ambulatory Medical Care Survey (NAMCS), to examine a comprehensive list of factors believed to be associated with visits where complementary health approaches were recommended or provided. NAMCS is a national health care survey designed to collect data on the provision and use of ambulatory medical care services provided by office-based physicians in the United States. Patient medical records were abstracted from a random sample of office-based physician visits. We examined several visit characteristics, including patient demographics, physician specialty, documented health conditions, and reasons for health visit. We ran chi-square analyses to test bivariate associations between visit factors and whether complementary health approaches were recommended or provided to guide development of logistic regression models. Of the 550,114 office visits abstracted, 4.43% contained a report that complementary health approaches were ordered, supplied, administered, or continued. Among complementary health visits, 87% of patient charts mentioned nonvitamin nonmineral dietary supplements. The prevalence of complementary health visits significantly increased from 2% in 2005 to almost 8% in 2015. Returning patient status, survey year, physician specialty and degree, menopause, cardiovascular, and musculoskeletal diagnoses were significantly associated with complementary health visits, as was seeking preventative care or care for a chronic problem. We present an overview of the first study of office-based physician visits where complementary health approaches were recommended or ordered to their patients. These data confirm the growing popularity of complementary health approaches in the United States, provide a baseline for further studies, and inform subsequent investigations of integrative health care.