The Medical Council of New Zealand (MCNZ) released their Statement on Complementary and Alternative Medicine (CAM) in March 2011, in order to inform doctors of the standards of practice that are expected of them if they have patients who use CAM.1

The key principle is that the Council does not oppose CAM use if it has "...demonstrated benefits for the patient...and patients have made an informed choice". The Council state that they endorse comments made in a Medical Practitioners Disciplinary Tribunal decision that "there is an onus on the practitioner to inform the patient not only of the nature of the alternative treatment offered but also the extent to which it is consistent with conventional theories of medicine and has, or does not have, the support of the majority of practitioners...". Further, the Council statement says that patients "must be aware of the likely effectiveness of a given therapy according to recognized peer-reviewed medical publications, notwithstanding your individual beliefs".

Some CAM therapies have been shown to be safe and effective, and others are scientifically plausible but only have weak evidence to support their use. However, there is no grey area with respect to homeopathy, a practice which involves diluting substances to such a degree that not a single molecule remains. An example of a homeopathic product is "Berlin Wall", which consists of dust from the Berlin Wall, diluted until none remains, sold to people to help them stop feeling repressed. It is not hard to see why the British Medical Association recently described homeopathy as witchcraft.2

A 2006 survey found that around 15% of New Zealand GPs will either administer homeopathy or refer patients to a homeopath,3 but this would appear not to be compatible with the Medical Council statement.

In terms of demonstrated benefits, there are none other than placebo effects.4 A US $1 million prize remains unclaimed for anyone who can demonstrate any in-vitro or in-vivo effects of any homeopathic product. Therefore the "likely effectiveness.... according to recognized peer-reviewed medical publications" is that there will be no benefits beyond those of a placebo.

With respect to "the extent to which it is consistent with conventional theories of medicine", this is also clear—homeopathy is biologically implausible and completely inconsistent with our understanding of medicine, biology, pharmacology and pathology.

Homeopathy does not have the support of the majority of medical practitioners, as demonstrated by the British Medical Association statement above and the 2006 New Zealand survey which found that most GPs say that it does not have benefits.2,3

Therefore in order for informed consent to occur according to the MCNZ statement, a doctor would have to say that:

The authors of this letter consider that practicing homeopathy, or endorsing it by referring patients, is not consistent with the ethical or regulatory requirements of practicing medicine, and call for doctors to do neither.