
Activated charcoal cleanses, also known as charcoal detoxes, are a pseudoscientific use of a proven medical intervention. Activated charcoal is available in powder, tablet and liquid form. Its proponents claim the use of activated charcoal on a regular basis will detoxify and cleanse the body as well as boost one's energy and brighten the skin. Such claims violate basic principles of chemistry and physiology. There is no medical evidence for any health benefits of cleanses or detoxes via activated charcoal or any other method. Charcoal, when ingested, will absorb vitamins and nutrients as well as prescription medications present in the gastrointestinal tract which can make it dangerous to use unless directed by a medical doctor.

In science and philosophy, an ad hoc hypothesis is a hypothesis added to a theory in order to save it from being falsified. Often, ad hoc hypothesizing is employed to compensate for anomalies not anticipated by the theory in its unmodified form.

AllTrials is a project advocating that clinical research adopt the principles of open research. The project summarizes itself as "All trials registered, all results reported": that is, all clinical trials should be listed in a clinical trials registry, and their results should always be shared as open data.

The American Humanist Association (AHA) is a non-profit organization in the United States that advances secular humanism, a philosophy of life that, without theism or other supernatural beliefs, affirms the ability and responsibility of human beings to lead personal lives of ethical fulfillment that aspire to the greater good of humanity.

Anomalistics is the use of scientific methods to evaluate anomalies, with the aim of finding a rational explanation. The term itself was coined in 1973 by Drew University anthropologist Roger W. Wescott, who defined it as being the "serious and systematic study of all phenomena that fail to fit the picture of reality provided for us by common sense or by the established sciences."

The Association for Skeptical Enquiry (ASKE) is a skeptical organisation in the United Kingdom.

The Brights movement is a social movement whose members since 2003 refer to themselves as Brights and have a worldview of philosophical naturalism.

The Center for Inquiry (CFI) is a US nonprofit organization that advocates strict church-state separation and opposes religion in government affairs.

The Comité Para, in full Comité belge pour l'Analyse Critique des parasciences, is a Francophone Belgian skeptical non-profit organisation. Founded in 1949, the Comité Para regards itself as the originator of the modern skeptical movement. The group's motto is Ne rien nier a priori, ne rien affirmer sans preuve.

Detoxification foot baths, also known as foot detox, ionic cleansing, ionic foot bath and aqua/water detox are pseudoscientific devices marketed as being able to remove toxins from the human body. They work by providing an electric current to an electrode array immersed in a salt water solution. When switched on, the electrodes rapidly rust in a chemical process called electrolysis which quickly turns the water brown. This reaction happens regardless of whether or not a person's feet are immersed in the water and no toxins from the human body have ever been detected in the water after use.

The Donation of Constantine is a forged Roman imperial decree by which the 4th-century emperor Constantine the Great supposedly transferred authority over Rome and the western part of the Roman Empire to the Pope. Composed probably in the 8th century, it was used, especially in the 13th century, in support of claims of political authority by the papacy. In many of the existing manuscripts, including the oldest one, the document bears the title Constitutum domini Constantini imperatoris. The Donation of Constantine was included in the 9th-century collection Pseudo-Isidorean Decretals.

The European Council of Skeptical Organisations (ECSO) is an umbrella of skeptical organisations in Europe.

The Freedom From Religion Foundation (FFRF) is an American non-profit organization, which advocates for atheists, agnostics, and non-theists. Formed in 1976, FFRF promotes the separation of church and state, and challenges the legitimacy of many federal and state programs that are faith-based. It supports groups such as nonreligious students and clergy who want to leave their faith.

The Friends of Science In Medicine (FSM) is an Australian association which supports evidence-based medicine and strongly opposes the promotion and practice of unsubstantiated therapies that lack a scientifically plausible rationale. They accomplish this by publicly raising their concerns either through direct correspondence or through media outlets. FSM was established in December 2011 by Loretta Marron, John Dwyer, Alastair MacLennan, Rob Morrison and Marcello Costa, a group of Australian biomedical scientists and clinical academics.

The Good Thinking Society is a nonprofit organisation promoting scientific scepticism established by Simon Singh in September 2012.

The Great Tantra Challenge was the challenge put forward to Surinder Sharma, a tantrik, by Sanal Edamaruku, the president of Rationalist International to kill him on live TV using only the magical powers he claims to possess. The challenge ended after several hours, with Edamaruku surviving unharmed. The event was broadcast live on India TV in March 2008.

A Kambo cleansing, also known as a Kambo circle or Kambo ceremony, Kambo, vacina-do-sapo, or sapo, is a purge using skin secretions of the kambô, a species of frog. The effects on humans usually include nausea, vomiting, and diarrhea; Kambo's usage produced several deaths. Kambo, which originated as a folk medicine practice among the Amazon indigenous peoples, is also administered as an alternative medicine treatment in the West, often as a pseudoscientific cleanse or detox. The ceremony involves burning an arm or leg and applying the Kambo secretion directly to the burn. Promoters claim that Kambo helps with several illnesses or injuries. There are ethnographic studies on the use of Kambo in traditional Noke Kuin medicine in the region of the state of Acre, in the Brazilian Amazon. Still, there is no scientific evidence that it is an effective treatment.

The New Inquisition is a book written by Robert Anton Wilson and first published in 1986. The New Inquisition is a book about ontology, science, paranormal events, and epistemology. Wilson identifies what he calls "Fundamentalist Materialism" belief and compares it to religious fundamentalism.

New Mexicans for Science and Reason is a science advocacy organization based in Albuquerque, New Mexico. Founded by Skeptical Inquirer editor Kendrick Frazier on May 16, 1990. As of 1998 the President is physicist and mathematician Dave Thomas. Thomas was still the President in spring of 2018 In 1996 creationists on the New Mexico School Board tried to change science standards to water down instruction of evolution. NMSR was instrumental in having that decision reversed.

NZ Skeptics is a New Zealand incorporated society created in 1986, with the aim of promoting critical thinking. The main areas of interest to the NZ Skeptics are claims of psychic abilities, alternative medicine, creationism and other pseudoscientific claims. At its founding in 1986, it was known as the New Zealand Committee for the Scientific Investigation of Claims of the Paranormal (NZCSICOP). In 2007 the name was formally changed to NZ Skeptics Incorporated.

RationalWiki is a wiki whose stated goals are to "analyze and refute pseudoscience and the anti-science movement, document 'crank' ideas, explore conspiracy theories, authoritarianism, and fundamentalism, and analyze how these subjects are handled in the media." It was created in 2007 as a counterpoint to Conservapedia after an incident in which contributors attempting to edit Conservapedia were banned.
The first Reason Rally was a public gathering for secularism and religious skepticism held on the National Mall in Washington, D.C. on March 24, 2012. The rally was sponsored by major atheistic and secular organizations of the United States and was regarded as a "Woodstock for atheists and skeptics". A second Reason Rally was held on June 4, 2016 at the Lincoln Memorial in Washington, D.C..
The Skeptic's Toolbox is an annual four-day workshop devoted to scientific skepticism. It was formed by psychologist and now-retired University of Oregon professor Ray Hyman, has been held every August since 1992, and is sponsored by the Committee for Skeptical Inquiry. The workshop focuses on educating people to be better critical thinkers, and involves a central theme. The attendees are broken up into groups and given tasks that they must work on together and whose results they must present in front of the entire group on the last day.

After School Satan is an after school program project of The Satanic Temple, an American political activist religious organization based in Salem, Massachusetts and is sponsored by Reason Alliance LTD, a 501(c)3 non-profit organization. It was created as an alternative to Christian-based after school groups, like the Good News Club.

The Skeptics' Guide to the Universe: How to Know What's Really Real in a World Increasingly Full of Fake is a 2018 book written by Steven Novella and co-authored by the other current co-hosts of The Skeptics' Guide to the Universe podcast—Bob Novella, Cara Santa Maria, Jay Novella, and Evan Bernstein. It also contains posthumous material from former co-host Perry DeAngelis. The book is meant to be an all-encompassing guide to skeptical thinking. In an interview with The European Skeptics Podcast, Jay Novella describes their approach to writing the book from the "point of view of an alien species observing the earth from a skeptical perspective using critical thinking," reminiscent of the book's namesake The Hitchhiker's Guide to the Galaxy by Douglas Adams.

Stichting Skepsis is a Dutch organisation dedicated to the promotion and practice of scientific skepticism. It is a member of the European Council of Skeptical Organisations (ECSO).

Voodoo Science: The Road from Foolishness to Fraud is a book published in 2000 by physics professor Robert L. Park, critical of research that falls short of adhering to the scientific method. Other authors have used the term "voodoo science", but it remains most closely associated with Park. The book is critical of, among other things, homeopathy, cold fusion and the International Space Station.

Young Skeptics is an after school program sponsored by The Better News Club, Inc. (BNC), an incorporated nonprofit organization run by a board of directors consisting of unpaid volunteers. Young Skeptics' mission statement says “The mission of Young Skeptics is to promote and facilitate critical thinking and evidence-based learning among the youth of local school districts. We believe in discovery through tangible problem solving and the scientific method, and refrain from offering supernatural explanations for occurrences in nature. Young Skeptics is committed to teaching children how to think, not what to think.” It ran a pilot program for elementary school children in Monroe County, New York. Young Skeptics is undergoing national expansion. Its first remote chapter will begin in February 2017 in San Luis Obispo, California.