Background: On May 5, 2016, the U.S. Food and Drug Administration (FDA) finalized a rule extending its authority to all tobacco products, including e-cigarettes, cigars, hookah tobacco and pipe tobacco, among others, which aims to help protect Americans from the dangers of tobacco and nicotine, especially the youth. The policy can be seen as a new intervention and become a hot discussion topic among the users in Twitter. Objective: This paper aims to examine the tweets related to the FDA's new policy in the social media, and gain a systematic understanding of users' responses to the intervention and the regulation. Methods: A total of 13864 tweets related to the policy from May 1st, 2016 to May 31st, 2016 were collected and analyzed, the support and opposition viewpoints about the six aspects including Regulation, Health, Industry, Democracy, Science, and Children were summarized, the time-sequence co-occurrence pattern of high-frequency words and the analysis of retweet and user dissemination network were analyzed. Results: Tweets are classified into six broad themes: Regulation, Health, Children, Industry, Science, and Democracy, the number of tweets about the six themes is 7547, 2764, 1678, 795, 670, 45. There are more supports on Regulation, Health, Science, and Children, the ratio of support(opposition) on the four themes are 80.6%(19.4%), 74.9%(25.1%), 85.9%(14.1%), 75.8%(24.2%), respectively, as for the themes of industry and democracy, most users hold the opposing view. The co-occurrence frequencies of gvaping. and "vape", "stocks" and "bigTobacco", "vapingsaveslives" and "vapeivote" are 328, 61, 104. A network with 222 retweets and 361 replies is constructed. Among the 361 replies, there are 62 negative replies accounting for 17.2%, 120 positive replies accounting for 33.2%, and 179 neutral replies accounting for 49.6%. It shows clearly that social media such as Twitter can be employed to gather valuable user feedback effectively and response on the government regulation.