In recent years, new synthetic drugs have spread rapidly in many parts of the world, and the risks of fatal overdoses are extremely high. The aim is to determine the features of the modern structure of narcotic drugs of the opioid group, which most often cause poisoning (overdose), and their toxic characteristics. Material and methods. A retrospective analysis of the data of the Toxicological Center of the Municipal Non-Commercial Enterprise «Kyiv City Clinical Ambulance Hospital» on the results of monitoring the structure of narcotic substances that caused acute poisoning (overdose) among the adult population of Kyiv in 1990–2020. Results. Over the past 10 years, the number of positive tests performed during the year for methadone has increased 150, morphine and tramadol — 100, heroin — 6 times; instead, the number of tests for natural opium («shirka») decreased by 7 times. Since 2017, cases of drug poisoning, which include various fentanyl analogues (acetylfentanyl, butyrylfentanyl, furanylfentanyl, etc.), have been regularly registered. It has been found that small amounts of new synthetic opioids are added to designer drugs (heroin, «ecstasy»), significantly increasing the risk of overdose and death on the street. The high toxicity of new synthetic opioids necessitates the improvement of existing protocols for the provision of medical care for opioid poisoning in the use of antidotes, tracheal intubation and pulmonary ventilation in the prehospital stage. Conclusion. Synthetic opioids are a new trend in the field of designer drugs, and the growing number of fatal poisonings associated with their use is creating new challenges for emergency physicians and toxicologists.