Complementary and alternative medicines (CAMs) are treatments that fall outside of mainstream healthcare.
These medicines and treatments range from acupuncture and homeopathy, to aromatherapy, meditation and colonic irrigation.
There's no universally agreed definition of CAMs.
Although "complementary and alternative" is often used as a single category, it can be useful to make a distinction between the 2 terms.
The US National Center for Complementary and Integrative Health (NCCIH) uses this distinction:
There can be overlap between these categories.
For example, aromatherapy may sometimes be used as a complementary treatment, and in other circumstances is used as an alternative treatment.
A number of complementary and alternative treatments are typically used with the intention of treating or curing a health condition.
To understand whether a treatment is safe and effective, we need to check the evidence.
You can learn more about the evidence for particular CAMs by reading about individual types of treatment.
See our index for a list of all conditions and treatments covered by the NHS website.
Some complementary and alternative medicines or treatments are based on principles and an evidence base that are not recognised by the majority of independent scientists.
Others have been proven to work for a limited number of health conditions.
For example, there's evidence that osteopathy and chiropractic practices are effective for treating lower back pain.
When a person uses any health treatment, including a CAM, and experiences an improvement, this may be due to the placebo effect.
The availability of CAMs on the NHS is limited, and in most cases the NHS will not offer such treatments.
The National Institute for Health and Care Excellence (NICE) provides guidance to the NHS on effective treatments that are value for money.
NICE has recommended the use of CAMs in a limited number of circumstances.
If you think you may have a health condition, first see your GP. Do not visit a CAM practitioner instead of seeing your GP.
It's particularly important to talk to your GP if you have a pre-existing health condition or are pregnant.
Some CAMs may interact with medicines that you're taking or should not be taken if you're pregnant.
The practice of conventional medicine is regulated by laws that ensure that practitioners are properly qualified and adhere to certain standards or codes of practice. This is called statutory professional regulation.
Professionals of 2 complementary and alternative treatments – osteopathy and chiropractic – are regulated in the same way.
There's no statutory professional regulation of any other CAM practitioners.
Osteopathy and chiropractic are regulated in the same way as conventional medicine.
Apart from osteopathy and chiropractic, there's no professional statutory regulation of complementary and alternative treatments in the UK.
If you decide to use a CAM, it's up to you to find a practitioner who will carry out the treatment in a way that's acceptable to you. Professional bodies and voluntary registers can help you do this.
Some regulated healthcare professionals, such as GPs, also practise unregulated CAMs.
In these instances, the CAM practice is not regulated by the organisation that regulates the healthcare professional (such as the General Medical Council), but these organisations will investigate complaints that relate to the professional conduct of their member.
Many CAMs have voluntary registers (some of which are accredited by the Professional Standards Authority for Health and Social Care, or the PSA) or professional associations that practitioners can join if they choose.
Usually, these associations or registers demand that practitioners hold certain qualifications and agree to practise to a certain standard.
Organisations with PSA-accredited voluntary registers include:
This means that these organisations have met the PSA's demanding standards, which are designed to help people make an informed choice when they're looking for a practitioner.
Once you have found a practitioner, it's a good idea to ask them some questions to help you decide if you want to go ahead with treatment.
You could ask: