Electronic cigarettes (e-cigarettes) are non-combustible devices that generate inhalable aerosols with major ingredients including: nicotine, propylene glycol, vegetable glycine, flavors, and various other substances. The global usage of e-cigarette has risen exponentially in recent years. Long-term safety of this electronic device has remained under-studied. Only a few crosssectional population-based studies have observed links between e-cigarette with increased risk of COPD, asthma, and respiratory symptoms, while other studies have found increased pulmonary inflammation and impaired lung function related to electronic cigarette use. After the debut of electronic cigarettes in the market, several case reports were published, attempting to establish the association of electronic cigarettes and respiratory illnesses covering lipoid pneumonia, acute eosinophilic pneumonia, acute hypersensitivity pneumonitis, diffuse alveolar hemorrhage, organizing pneumonia, and respiratory bronchiolitis interstitial lung disease. Most recently, a case series published in 2019 has reported a large cluster of unknown pulmonary illnesses that may be associated with e-cigarette use. Liquids and aerosols in e-cigarettes contain a great variety of chemical constituents. Moreover, thermal decomposition and heating coils could produce new compounds in vaporizing aerosols. As noted above, no single product or material was identified as a major cause. Naming vaping lung injury EVALI (electronic cigarette or vaping product use associated lung injury), the US Centers for Diseases Control and Prevention does not recommend the use of e-cigarette for smoking cessation as there is no sufficient evidence indicating its effectiveness. Instead, CDC urges people to refrain from using e-cigarette before its health concerns are clarified through full-scale investigations. Medical professionals should be concerned about the impacts of e-cigarette on respiratory health.