• What is Complementary and Alternative Medicine (CAM)?
  • Why establish a CAM website?
  • What information is on this website?
  • What topics are initially covered?
  • Levels of Evidence
  • The publishers of this website
  • Other useful sources of CAM information
  • How can referenced articles be obtained?

What is Complementary and Alternative Medicine (CAM)?

Complementary and alternative medicine (CAM) is a broad domain of healing resources that encompasses all health systems, modalities, and practices and their accompanying theories and beliefs, other than those intrinsic to the politically dominant health system of a particular society or culture in a given historical period. CAM includes all such practices and ideas self-defined by their users as preventing or treating illness or promoting health and well-being. Examples of CAM include acupuncture, chiropractic, herbal medicine, homoeopathy, and osteopathy.

Why establish a CAM website?

Information about the safety and usefulness of CAM is important for users of health services and health practitioners. With so much information available on the Internet, it can be hard to know which information sources are reliable. For this reason, the Ministry of Health has commissioned this website. The New Zealand Guidelines Group was contracted in 2005 by the Ministry to establish the website and develop the evidence summaries.

The information on this website was intended to assist the Ministerial Advisory Committee on Complementary and Alternative Health in meeting its terms of reference (for more information about this Committee visit www.newhealth.govt.nz/maccah.)

What information is on this website?

This website provides high-quality information about CAM, and links to other reliable information sources. The website is intended to be New Zealanders’ first port of call for evidence-based information on CAM treatments.

This website provides summaries of evidence that are free from technical jargon so that they are easy to understand. The site also contains important safety alerts regarding CAM. The website is aimed at a wide audience, including consumers and health practitioners of all disciplines. Many health practitioners are interested in using CAM treatments where they are supported by evidence.

What topics are initially covered?

Since CAM is such a broad field, five therapies were identified to initially focus on. These therapies are Acupuncture, Chiropractic, Herbal Medicine, Homoeopathy, and Osteopathy. With time we will expand this website to cover other forms of CAM.
Levels of Evidence


When developing the evidence reports, studies of various designs are assessed using a grading system developed by NZGG (see Table 1).

There are many different evidence grading systems in international use. These systems are used to show how well a study was able to answer a question and how reliable or uncertain that answer is. Both study design and quality are considered in this process.

This CAM system has been devised to be compatible with the other grading systems used by NZGG and also to map to other international systems (see Table 2).

Due to the emerging nature of the evidence for complementary and alternative therapies, many studies are non-randomised or uncontrolled. Often no Level 1 or 2 evidence is available. Sometimes Level 1 or 2 studies cannot be carried out because it would involve a safety risk for participants. Sometimes it would be too difficult to carry out a Level 1 or 2 study large enough to measure rare effects. In these instances evidence is based on lower level studies.

Lower level evidence is subdivided into Levels 3 and 4. This serves to illustrate a progression that may occur when investigating CAM from Level 4 through Levels 3 and 2 to Level 1 evidence.

Although possible harms and adverse events are important aspects of any CAM, they are often only reported from lower level studies. Higher level evidence is not often available for the reasons stated above.

A range of expert opinion also exists. In other grading systems, this is usually included in a fifth level. This level of evidence has not been reviewed for these reports.


Table 1: Levels of evidence used in Evidence Reports for www.cam.org.nz.

Level of evidence Where the evidence comes from
1 Evidence with a high degree of reliability Studies that use well-tested methods to make comparisons in a fair way and where the results leave very little room for uncertainty.


Trial design: usually Level 1 studies are systematic reviews or large, high-quality randomised controlled studies.

2 Evidence with reliability but open to debate Studies that use well-tested methods to make comparisons in a fair way but where the results leave room for uncertainty (for example, due to the size of the study, losses to follow-up or the method used for selecting groups for comparison).


Trial design: usually Level 2 studies are systematic reviews without consistent findings, small randomised controlled trials, randomised controlled trials in which large numbers of participants are lost to follow-up, or cohort studies.

3 Some evidence without a high degree of reliability Studies where the results are doubtful because the study design does not guarantee that fair comparisons can be made.


Trial design: usually Level 3 studies are systematic reviews of case-control studies or individual case-control studies.

4 Some evidence but based on studies without comparable groups. Studies where there is a high probability that results are due to chance (for example because there is no comparison group or because the groups compared were different at the outset of the study).


Trial design: usually cohort or case-control studies where the groups were not really comparable, or case-series studies.


For further information on the Levels of Evidence click here

The publishers of this website

The CAM website was established in March 2004 and is funded by the New Zealand Ministry of Health.  In August 2005, the New Zealand Guidelines Group was contracted to maintain and develop the website further.

Other useful sources of CAM information

If you cannot find what you want on this website, try using some of the resources listed on the Links page, or visit the PubMed site.

How can referenced articles be obtained?

The PubMed database has a summary of many (but not all) of the references used in the evidence summaries on this website. To look up the summary of an article, print off these instructions (PDF document, size 112 kilobytes) and follow them step by step. To obtain full articles referenced in the evidence summaries we suggest you contact your local library. In many cases this will result in an “interlibrary loan request” being placed on your behalf. Please note that this service is not always free. Charges may vary depending on the fees imposed by the library supplying the article.