N′-nitrosonornicotine (NNN), 4-(methylonitrosoamino)-1-(3-pirydyl)-l-butanone (NNK) and N′-nitrosoanatabine (NAT) are the three most representative tobacco-specific nitrosamines (TSNAS) in E-cigarettes. Kim, H.J. et al. tested the content of TSNAS in e-liquid samples. There were various kinds of TSNAS tested in 105 samples, among which the maximum concentration of NAT reached 62.19 ug/L, significantly exceeding the requirement for cigarette companies . Nitrosamines have strong carcinogenicity. Moreover, both nitrosamine and the polycyclic aromatic hydrocarbon benzopyrene can interact with DNA. These produced additives interfere DNA replication and the duplicated DNA produces purine free sites and triggers gene mutations . The chemical mixture in the smoke of the E-cigarette will cause chromosome division, and may cause damage to mitotic spindles or filaments, thereby inducing mutations .