Background: Predatory journals pose an emerging issue in scientific literature, particularly in medicine. They collect publication fees and publish papers without sufficient peer review, wasting researchers’ time and financial resources, without providing any customer service for the authors. Consequently, predatory journals contribute to a decline in public trust in the credibility of scientific literature. Objective: This scoping review aimed to identify and map the impact of predatory journals on the scientific community. Methods: A comprehensive search for relevant manuscripts published until January 2024 was conducted in PubMed, Scopus, Embase, Web of Science, and the Cochrane Library databases. We included studies that describe Predatory Journals, quantitative and qualitative articles, and review articles. Exclusion criteria were papers that did not report information about Predatory Journals. The search was performed with a combination of Medical Subject Headings (MESH) and entry terms, including “Predatory Journals as Topic” OR "Predatory Journal". No language restrictions were applied. Two authors independently screened the search results based on titles and abstracts, with duplicate studies being excluded. Finally, the selection of the studies was summarized in a flow diagram. Results: In total, 916 articles were retrieved from databases. Twenty-seven studies were selected for the analysis. The main impacts of potentially predatory journals are: that they publish fraudulent or inconsistent research in exchange for money without analyzing their methodological quality; do not meet the requirements of the “peer-review” system; and publish any article highlighting supposed therapeutic efficacious; it calls into question scientific credibility and interferes with the contribution to the knowledge base. Conclusions: The impact of these journals extends beyond the financial burden on researchers, as they compromise the integrity and reliability of published research. Including the dissemination of false therapeutic efficacy, which can even change therapeutic adherence in society.