The companies publishing predatory journals are an emerging problem in the area of scientific literature as they only seek to drain money from authors without providing any customer service for the authors or their readership. These predatory journals try to attract new submissions by aggressive email advertising and high acceptance rates. But in turn, they do not provide proper peer review, and therefore, the scientific quality of submitted articles is questionable. This is important because more and more people, including patients, are reading such journals and rely on the information they provide. Consequently, predatory journals are a serious threat to the integrity of medical science, and it is crucial for scientists, physicians and even patients to be aware of this problem. In this review, we briefly summarize the history of the open access movement, as well as the rise of and roles played by predatory journals. In conclusion, young and inexperienced authors publishing in a predatory journal must be aware of the damage of their reputation, of inadequate peer review processes and that unprofitable journals might get closed and all published articles in that journal might be lost.