Background:Nicotine absorbed by the skin and also by the digestive, respiratory and excretory systems is one of the most known toxins found in tobacco. This work reviews available literature on the influence of nicotine on human health, and in particular on the oral cavity. Material/Methods: A review of literature related to the topic of the paper. Results:Numerous studies indicate that nicotine adversely affects human health. It exerts a negative effect at the cellular level by modifying metabolism, and disturbs the interactions between tissues, which strongly promotes the formation of cancer-like changes. Nicotine causes numerous pathologies in the respiratory, immune, and cardiovascular systems leading to a number of metabolic disorders. Conclusions: The intake of nicotine contained in tobacco products has a particularly negative effect on the oral cavity. It accelerates periodontitis, with weaker clinical symptoms associated with resistance to conventional treatment. In addition, nicotine changes the oral cavity microflora, increasing the amount of harmful bacteria and pathogenic fungi.