Can buying an electronic cigarette help you quit smoking? It is always a big question, or a controversy in the society about public health and even community safety, especially in the USA, where smokers and vapers are both very common. Indeed, ecig is now considered one of the most useful solutions for the group of people who have being concerned about how to quit smoking. Many believe that if ecig is adopted as a substitute to cigarettes, it can help more people to quit smoking. On top of that, they can increase the associated health and financial benefits that come with this by cutting the use of conventional cigarettes. On the other hand, though an ecig generally enjoys a very high safety, many are still worried about people many use an electronic cigarette as a complement to conventional cigarettes, i.e. to use both kinds of cigarettes together. Such kind of people are not rare, and are called "complementers" by some. When ecigs are treated as a complementary product, people will simply blunt the regular anti-smoking regulation and keep themselves smoking for even longer. According to an online survey of 2,406 people conducted in the US, 37 per cent of smokers who use e-cigarettes view electronic cigarettes mainly as a complementary product to the conventional cigarettes, rather than a substitute to them. Also, the survey found that 55 per cent of “substituters” were trying to quit smoking, while only 40% of the "complementers" were. 37 per cent of complementers in our sample regarded vaping primarily as a complementary activity to smoking, while only 27 per cent of non-smokers thought electronic cigarettes would be used in this way rather than as a substitute. Such fact gives us an insight that some people, especially the non-smokers, overestimate the benefits of ecig to the question of "how to quit smoking".