Objective: The aim of this study is to examine the use of dietary supplements (vitamin-mineral and herbal products) by adults during the COVID-19 pandemic. Materials and Methods: The descriptive and cross-sectional study was performed between May 2021 and August 2021. The study was conducted on 402 adults aged between 18-65 years old. An online questionnaire was used as a data collection tool. Results: 58.7% of the participants were female, 41.3% male (mean age; 36.3±11.7 years), and 77.9% of them were university or postgraduate degrees. 15.4% stated that they were diagnosed with COVID-19. 66.2% of the participants used dietary supplements during the pandemic. Participants’purposes for using nutritional supplements were to ‘strengthen the immune system’ (72.9%), ‘feel good’ (44.0%), ‘protect from COVID-19’ (39.1%) and ‘eliminate body deficiency’(35.7%), respectively. It was determined that more than half of the participants believed that dietary supplements were protective against COVID-19 and that the majority (80.6%) of those diagnosed with COVID-19 started using dietary supplements. It was determined that the participants obtained information about dietary supplements mostly from the mass media; health professionals, mass media and the social environment were effective in the decision to use dietary supplements The most used dietary supplements during the pandemic were C, D, B group vitamins, ginger, cinnamon, green tea and turmeric. In the study, it was found that gender, educational status, place of residence, marital status, income, occupation, chronic disease status, COVID-19 diagnosis were effective in the use of dietary supplements. Conclusion: As a result of the research, it was revealed that the use of dietary supplements by adults increased during the COVID-19 pandemic. Although dietary supplements are used to support nutrition or strengthen immunity, they cause health-impairing effects as a result of incorrect information and unconscious use. For this reason, it is important to use dietary supplements under the control of specialists such as a doctor or dietitian and to raise awareness about their effects on health.