Evidence basis

Naturopathy lacks an adequate scientific basis under the methodology of evidence-based medicine (EBM). Members of the medical community show a critical or rejecting view of naturopathy. Traditional naturopathic practitioners surveyed in Australia perceive EBM as an ideologic assault on their beliefs in vitalistic and holistic principles. They advocate the integrity of natural medicine practice. Traditional natural medicine practitioners surveyed in Australia could have problems in understanding and applying the concept of EBM. If naturopathy offers verifiable results for specific conditions, greater scientific knowledge of the mechanisms of those naturopathic protocols could result in improved therapy models. Some naturopathic physicians have begun to contribute to research and adapt modern scientific principles into clinical practice.

There are growing collaborative efforts between naturopaths and medical doctors to evaluate the safety and efficacy of naturopathic medicine in prevention and management of a broad range of common ailments, and to decide whether accessibility of naturopathic services will enhance patient health in a cost-effective way. In Germany a host of naturopathy alternative treatments are sold as reliable science such as reflexology. However, even among those who support naturopathy consider reflexology unscientific. Contrary to reflexology, scientifically genuine naturopathic methods are not an alternative, but a supplement to modern medicine.

Naturopathy is criticized for its reliance on and its association with unproven, disproven, and other controversial alternative medical treatments, and for its vitalistic underpinnings. As with any alternative care, there is a risk of misdiagnosis; this risk may be lower depending on level of training. There is also a risk that ailments that cannot be diagnosed by naturopaths will go untreated while a patient attempts treatment programs designed by their naturopath. Certain naturopathic treatments, such as homeopathy, rolfing, and iridology, are widely considered pseudoscience or quackery. Natural methods and chemicals are not necessarily safer or more effective than artificial or synthetic ones; any treatment capable of eliciting an effect may also have deleterious side effects.

"Non-scientific health care practitioners, including naturopaths, use unscientific methods and deception on a public who, lacking in-depth health care knowledge, must rely upon the assurance of providers. Quackery not only harms people, it undermines the ability to conduct scientific research and should be opposed by scientists", says William T. Jarvis.

Stephen Barrett of Quackwatch and the National Council Against Health Fraud has stated that the philosophy of naturopathy is "simplistic and that its practices are riddled with quackery."

K. C. Atwood writes, in the journal Medscape General Medicine, "Naturopathic physicians now claim to be primary care physicians proficient in the practice of both "conventional" and "natural" medicine. Their training, however, amounts to a small fraction of that of medical doctors who practice primary care. An examination of their literature, moreover, reveals that it is replete with pseudoscientific, ineffective, unethical, and potentially dangerous practices." In another article, Atwood writes that "Physicians who consider naturopaths to be their colleagues thus find themselves in opposition to one of the fundamental ethical precepts of modern medicine. If naturopaths aren't to be judged "nonscientific practitioners," the term has no useful meaning. An article by a physician exposing quackery, moreover, does not identify its author as "biased," but simply as fulfilling one of his ethical obligations as a physician."

According to Arnold S. Relman, the Textbook of Natural Medicine is inadequate as a teaching tool, as it omits to mention or treat in detail many common ailments, improperly emphasizes treatments "not likely to be effective" over those that are, and promotes unproven herbal remedies at the expense of pharmaceuticals. He concludes that "the risks to many sick patients seeking care from the average naturopathic practitioner would far outweigh any possible benefits."