This work is based on clinical observations (over 300 patients with drug allergies) and an analysis of more than 1,500 works by domestic and foreign authors and this issue. Based on these data, a detailed analysis of immediate and late complications of drug treatment was made, the main spmptomatnka of acute and delayed forms of drug allergy was presented, clinical options for the disease, issues of its immediate and long-term prognosis, relationship with other nosological forms, in particular, with systemic vascular and reticulo-endothelial diseases were considered.