It concerns those "that are not supported by testably logical or empirically viable hypotheses and theories" and/or "that are actively distributed amongst the public, while no testing on its efficaciousness and safety has taken place within the professional group".

The VtdK stresses that "the term kwakzalver ("quack") or kwakzalverij ("quackery") does not necessarily constitute an accusation of bad faith or fraud.

[15] Past chair Catherine de Jong responding to a question about the makeup of members, stated that about half are involved in the medical profession.

The aforementioned list of "greatest quacks of the 20th century" included Mayita Sickesz, a Dutch doctor who claims to be able to cure autism, depression, schizophrenia and several other diseases through an unconventional treatment similar to chiropractic health care.

[19] The verdict was much criticized[20] and Netherlands national newspaper de Volkskrant listed it as number one in their top ten of legal failures that year.

[21] The verdict was overturned in May 2009, because a judge decided that using a narrow definition of the word kwakzalver ("quack") that a previous ruling was forcing the group to defend in a libel case, was incompatible with Article 10 of the European Convention on Human Rights.

After her death the public prosecutor pressed charges against two alternative health care providers and the self-proclaimed "healing medium" Jomanda.

At this point the Vereniging tegen de Kwakzalverij together with Stichting Skepsis took legal steps forcing the prosecutor to continue his case.

The case created a stir in Dutch media and was used as a pretense to remove a range of alternative medical procedures from health insurance coverage in The Netherlands, effectively making them too expensive for much of the public.