Diseases and deaths due to smoking are still a major public health problem, which is still the leading cause of death in the world. Today, the harmful effects of active smoking and second hand cigarette smoke on health are clearly known. However, the concept of third-hand smoke (THS) exposure, a new concept, is a relatively new definition in the area of environmental and public health. The third-hand smoke (THS) consists of residual cigarette smoke gases and particles that settle on the surface. Studies evaluating the presence of tobacco specific nitrosamines (TSNA) in house dust samples have shown that THS is an important source of exposure to TSNA. Investigations on animals estimating human exposure, it has been found that THS contains tobacco smoke compounds, which can stay for months on internal surfaces and in dust for months, and that it is re-released into the air as gaseous. In addition, surface chemicals in the surroundings and in dust can produce additional toxins as a result of various chemical reactions. Although it is premature to estimate the health impacts of THS as a whole, the health effects of TSNAs have been previously reported in the literature. Future studies should be directed at investigating the biological effects and consequences of THS on humans. This article will address the implications of THS exposure and the results of current studies conducted in this area.