The public understanding of science has produced a large body of research about general attitudes toward science. However, most studies of science attitudes have been carried out via surveys or in experimental conditions, and few make use of the growing contexts of online science communication to investigate attitudes without researcher intervention. This study adopted corpus-based discourse analysis to investigate the negative attitudes held toward science by users of the social media website Reddit, specifically the forum r/science. A large corpus of comments made to r/science was collected and mined for keywords. Analysis of keywords identified several sources of negative attitudes, such as claims that scientists can be corruptible, poor communicators, and misleading. Research methodologies were negatively evaluated on the basis of small sample sizes. Other commenters negatively evaluated social science research, especially psychology, as being pseudoscientific, and several commenters described science journalism as untrustworthy or sensationalized.