This is a list of topics that have, at one point or another in their history, been characterized as pseudoscience by academics or researchers. Detailed discussion of these topics may be found on their main pages. These characterizations were made in the context of educating the public about questionable or potentially fraudulent or dangerous claims and practices—efforts to define the nature of science, or humorous parodies of poor scientific reasoning.
Criticism of pseudoscience, generally by the scientific community or skeptical organizations, involves critiques of the logical, methodological, or rhetorical bases of the topic in question. Though some of the listed topics continue to be investigated scientifically, others were only subject to scientific research in the past, and today are considered refuted but resurrected in a pseudoscientific fashion. Other ideas presented here are entirely non-scientific, but have in one way or another impinged on scientific domains or practices.
Many adherents or practitioners of the topics listed here dispute their characterization as pseudoscience. Each section here summarizes the alleged pseudoscientific aspects of that topic.