The open access (OA) publishing, where a reader-pays economy has been replaced by an author-pays model, began at the end of the 20^th century. This movement arose as an attempt to avoid excessive costs and copyright transfer agreements inherent to the subscription model. Favored by the extended use of the internet, OA academic journals have multiplied during the last decades. However, an unintended side effect of the OA model has been the numerous predatory journals that have appeared over the past years¹. Predatory journals and publishers are entities that prioritize self-interest at the expense of scholarship and are characterized by false or misleading information, deviation from best editorial and publication practices, a lack of transparency, and/or the use of aggressive and indiscriminate solicitation practices². These journals publish the submitted material without external peer review, and the term “predatory” refers to the financial profit through article processing charges³. Predatory journals have low-budget websites with grammatical errors; their editors’ names are not recognizable in the field of interest; they guarantee rapid publication times; manuscripts are submitted by e-mail and not through formal online submission processes; require submission fee regardless of acceptance; use journal names similar to those of reputable journals; do not discuss copyright; do not have retraction policy after submission; a peer-review process is not mentioned; contact information is not provided; and ethics policies are not mentioned⁴.

The number of articles published by predatory journals has rapidly increased from 53,000 in 2010 to an estimated 420,000 in 2014, published by around 8000 active journals. By 2015, there were as many as 10,000 predatory journals worldwide⁵. Articles published in predatory journals tend to be of low quality and usually fail to report key information that allows to reproduce the findings, for example, methods and results are poorly described; clinical trials are not registered in databases; and studies lack ethics committee approval⁶.

The predatory market is a complex phenomenon. It all starts with predatory publishers addressing inexperienced students who are their easy prey, or experienced researchers, who opt for predators after being rejected by legitimate journals. In addition, the pharmaceutical industry sponsors predatory publishers such as the OMICS Publishing Group⁷, a company involved in unfair and deceptive practices, hosting numerous conferences of dubious quality each year and publishing more than 700 journals⁸. Moreover, many of these publications are currently indexed in PubMed⁹, and predatory journals have been included in the lists of reputable journals like the one elaborated by the Journal registration in the International Committee of Medical Journal Editors¹⁰. Thus, considering that predatory journals have found the ways to penetrate databases², and blacklists of predators will never be updated enough, the combination of filters shown in table 1 is recommended for identification of legitimate OA journals.

Predatory publishing represents an enormous global market leading to dissemination of low-quality research, which may be considered as pseudo-science. Therefore, predatory publishing is obviously unethical and damages the credibility of researchers and their institutions. However, scientists are not defenseless against predators, so participating in this market as authors or by citation of such publications is elective. The sequence of steps for the detection of predatory journals presented here should be continuously updated because these journals and their publishers rapidly adapt to filters that might discredit them¹¹.

Finally, the question that arises is whether sponsorship of pharmaceutical industry to predatory publishers might stimulate the non-evidence-based prescription and consumption of drugs in low- and middle-income countries.