Tanacan E, Dincer D, Erdogan FG, et al. - Given that the Systemic Immune‐Inflammation Index (SII) (neutrophils × platelets/lymphocytes) has been widely used in oncology since 2014, with promising outcomes, researchers performed this retrospective cohort study to evaluate the efficiency of the SII in determining the activity of Behçet disease (BD). The sample consisted of BD patients who were admitted to the outpatient clinic of the Department of Dermatology and Venereology, Ufuk University Hospital, between January 1, 2010, and December 31, 2019. In the active disease group, higher numbers of white blood cells, platelets and neutrophils, higher red cell distribution width, higher erythrocyte sedimentation rate, C‐reactive protein and ferritin levels, and higher SII were noted. Findings suggested that the SII may be used as an additional indicator for the evaluation of BD status and doctors should be careful in patients with SII levels of > 552 × 10³/mm³) at the initial assessment of the patients.