As part of the school of preventive medicine at KGU secondary school No. 25 Pavlodar 14/03/2025 under the leadership of head. Department of OVP, Professor A.A. Dyusupova and academic mentor Ph.D. Acting Associate Professor Adilgozhina S.M. A lesson was held among on the topic “Electronic cigarettes – harm and consequences”.  Both cigarettes and vape systems have a detrimental effect on health. But if we know almost everything about nicotine, there has been a fierce fight against smoking in recent years and there are positive results, then the popularity of electronic cigarettes and vapes has not yet decreased, and although there is more information about them, the full impact has not yet been fully studied. The popularity of vapes among teenagers is of particular concern. A person who is hooked on this product uses it more often, since flavors make the smoking process easier, which means the load on the body increases. And it’s not just about the respiratory system. It is known that the composition of vape system liquids includes propylene glycol, glycerin, nicotine, diacetyl, aromatic additives, and when inhaling steam, heavy metal ions enter the body – tin, nickel and others. How do they affect the endocrine system? For example, pentabromodiphenyl ethers, which are responsible for keeping the device cool, disrupt the production of thyroid hormones, which regulate the functioning of the heart and brain. Flavors and heavy metals have a carcinogenic effect on endocrine glands – hormones with high biological activity that ensure the processes of growth, development, reproduction, adaptation, behavior. Therefore, the use of vapes in adolescence is especially dangerous, when the body is still growing and has not encountered such a load.