The main aim of this study was to assess the frequency of use of complementary and alternative medicine (CAM) in patients admitted to the emergency room (ER). Additionally, we aimed to evaluate the socio-demographic and clinical factors associated with CAM use.This was a descriptive study. A total of 951 patients who were admitted to the ER of a tertiary hospital between October 2018 and November 2018 were enrolled. Data were obtained using a questionnaire that was prepared by the researchers considering the literature data.The mean age of the patients was 37.98 ± 15.65 years. Of the 951 patients, 48.4% ( = 460) were female and 51.6% ( = 491) were male. The rate of patients who used CAM at least once was 47.3% ( = 450). The most frequently used CAM methods were herbal therapy (68.9%), massage (40.7%), dietary supplements (24.7%), and hijama (24.2%). Being aged 64 years or younger ( = 0.001), having an education level of university or higher ( = 0.006), having an income more than minimum wage ( = 0.016), and having a chronic disease ( = 0.003) were found to be associated with CAM use in this study.CAM methods were used by a considerable proportion of patients admitted to the ER. Physicians should incorporate CAM use history in their patient assessments and should provide accurate and unbiased information about CAM methods.