When e-cigarettes and, later on, heat-not-burn products were introduced to the market, it was hypothesized that they could have some positive effect on smoking cessation and reduction of smokers’ exposure to dangerous substances. Despite some of their benefits, toxicological studies show the presence of some hazardous substances in their vapors, which may affect smokers’ health in a similar way as tobacco cigarette compounds. There is a small amount of research studying the effects of these alternative cigarettes on health consequences in humans. In addition, the great majority of them compare only health effects of switching to e-cigarettes or heat-not-burn (HnB) products, without specifying their impact on non-smokers. Long-term exposure effects of e-cigarettes and heat-not-burn cigarettes and their effect on maternal health or fetus development are still unknown.