From the EditorsDear readers,We are honoured to greet you with the first issue of 2018. This issue contains two reports, four original articles and one two from the editor. The title of the first report is “Physicians' social media use and ethics”. In her report, Avcı discusses ethical issues with specific examples, and investigates the key issues found in the preparation of social media guidelines. The second report deals with intestinal microbiota and health. In their report, Kalip et al. investigate the roles of gastrointestinal microbiota on immune system functions, as well as on the regulation of the metabolism.The original articles published in this issue cover many important public health issues. The first, conducted by Çamur et al....