Summary In recent years, various products and devices for inhalation of vapor have appeared - electronic nicotine deli­very systems (ENDS). The review presents the study of the composition of the vapor of various means of nicotine delivery, including ultrafine particles, flavors, nicotine, as well as various toxic and carcinogenic substances. Most studies find in the composition of steam ENDS potentially hazardous substances, but in smaller quantities than in cigarette smoke. Currently, the degree of risk to health from higher than in ambient air levels of these compounds and elements, has not been established. Longer research is needed to assess the effect of ENDS on human health and tobacco use, but an increased concentration of toxic substances compared to background levels cannot be completely safe, and therefore creates increased health risks for both users of these devices and others.