The placebo effect and complementary and alternative medicine

When a person uses any type of health treatment and sees an improvement in their symptoms, they may be experiencing the placebo effect.

For hundreds of years, doctors have known that when a patient with a health condition expects their symptoms to improve, they often do improve.

Today, we know that patients who are given empty injections or pills that they believe contain medicine can experience an improvement in a wide range of health conditions.

This kind of fake or empty medicine is often called a "placebo", and the improvement this causes is called the "placebo effect".

It can affect all of us and can occur when a person uses any kind of health treatment – either conventional or complementary and alternative.

It’s important to be aware of the placebo effect when choosing complementary and alternative medicines (CAMs).

If you choose a complementary or alternative treatment that does not work – and only causes a placebo effect – you may miss out on more effective treatments.

This page covers:

Examples of the placebo effect

CAMs and the placebo effect

Checking the evidence for or against a treatment

Examples of the placebo effect

One well-known example of the placebo effect involves a physical feeling we are all familiar with: pain.

In 1996, scientists assembled a group of students and told them that they were going to take part in a study of a new painkiller, called "trivaricaine".

Trivaricaine was a brown lotion to be painted on the skin, and that smelled like a medicine. But the students were not told that, in fact, trivaricaine contained only water, iodine and thyme oil – none of which are painkilling medicines. It was a fake – or placebo – painkiller.

With each student, the trivaricaine was painted on one index finger, and the other left untreated. In turn, each index finger was squeezed in a vice. The students reported significantly less pain in the treated finger, even though trivaricaine was a fake.

In this example, expectation and belief produced real results. The students expected the "medicine" to kill pain; and, sure enough, they experienced less pain. This is the placebo effect.

Read a summary of the study: Mechanisms of Placebo Pain Reduction.

Placebo medicine has even been shown to cause stomach ulcers to heal faster than they otherwise would.

These amazing results show that the placebo effect is real, and powerful. They mean that fake or placebo treatments can cause real improvements in health conditions.

Experiencing the placebo effect is not the same as being "tricked", or being foolish. The effect can happen to everyone, however intelligent, and whether they know about the placebo effect or not.

CAM and the placebo effect

Evidence about a treatment is gathered by conducting fair tests. In these tests, scientists find out whether a treatment causes an improvement beyond the improvement caused by the placebo effect alone.

Evidence plays an important role in mainstream medicine. This means that when you use many conventional medicines, you can be sure there is evidence they work.

When patients experience improvement after using a healthcare treatment that has not been proven to work, they may only be experiencing the placebo effect.

Of course, improvement in a health condition due to the placebo effect is still improvement, and that is always welcome.

But it is important to remember that for many health conditions, there are treatments that work better than placebos. If you choose a treatment that only provides a placebo effect, you will miss out on the benefit that a better treatment would provide.

Checking the evidence for or against a treatment

The only way to know whether a health treatment works better than a placebo treatment is by checking the evidence.

Evidence, CAM and the NHS

The National Institute for Health and Care Excellence (NICE) uses evidence when it draws up guidance for the NHS on the use of treatments and the care of patients.

Currently, NICE recommends the use of a complementary and alternative treatment in a limited number of instances, including:

• Alexander Technique for Parkinson’s disease
• ginger and acupressure for reducing morning sickness
• manual therapy for low back pain

You can read about the evidence for different CAMs on pages about specific treatments. See our index for a list of all treatments covered by NHS Choices.

How evidence is gathered and used

The best way to produce good evidence on a health treatment is to conduct a fair test. Here, the medicine or treatment being tested is compared to another treatment, or to a placebo.

Tests are made as fair as possible by minimising bias and the role of chance. This means that the test results will reflect, as far as possible, the truth about the medicine or treatment, and will not be influenced by other factors, such as the way the test was carried out, or the attitudes of the people who take part.

Scientists often call these fair tests clinical trials.

Before scientists conclude that a health treatment is safe and that it works, there must usually have been several independent tests of the treatment that have shown this.

Sometimes, different fair tests can give results that disagree.

The results of fair tests can provide:

• results that show the medicine or treatment does work and is safe; this is often call positive evidence, or evidence for the treatment
• results that show the medicine does not work, or is unsafe; this is often called negative evidence, or evidence against the treatment

Negative evidence – that is, evidence against a treatment – is not the same as no evidence. Negative evidence means a set of results showing that a medicine or treatment does not work.

No evidence simply means an absence of any evidence, because fair tests have not been conducted.

Where to find out more

• Read about the evidence for different CAMs on pages about specific treatments. See our index for a list of all treatments covered by NHS Choices.
• Search for evidence on any treatment on the NHS Evidence website.

Complementary and alternative medicine

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.

This page covers:

Defining CAMs

Deciding to use complementary or alternative treatments

Availability on the NHS

Finding a CAM practitioner

Defining CAMs

There is 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 two terms.

The US National Center for Complementary and Integrative Health (NCCIH) uses this distinction:

• When a non-mainstream practice is used together with conventional medicine, it's considered "complementary".
• When a non-mainstream practice is used instead of conventional medicine, it's considered "alternative".

There can be overlap between these two 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.

Examples include:

• homeopathy
• acupuncture
• osteopathy
• chiropractic
• herbal medicines

Deciding to use complementary or alternative treatments

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 NHS Choices.

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 is evidence that osteopathy and chiropractic 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.

CAMs and the NHS

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.

For example:

• the Alexander technique for Parkinson's disease
• ginger and acupressure for reducing morning sickness
• manual therapy for lower back pain

Finding a CAM practitioner

If you think you may have a health condition, first see your GP. Don't 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 are taking.

CAMs and regulation

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 two complementary and alternative treatments – osteopathy and chiropractic – are regulated in the same way.

There is no statutory professional regulation of any other CAM practitioners.

Finding an osteopath or chiropractor

Osteopathy and chiropractic are regulated in the same way as conventional medicine.

• All osteopaths must be registered with the General Osteopathic Council. You can use the General Osteopathic Council website to find a registered osteopath near you, or check if someone offering osteopathic services is registered.
• All chiropractors must be registered with the General Chiropractic Council. You can use the General Chiropractic Council website to find a registered chiropractor near you, or to check if someone offering chiropractic services is registered.

Finding other CAM practitioners

Apart from osteopathy and chiropractic, there is no professional statutory regulation of complementary and alternative treatments in the UK.

This means:

• it is legal for anyone to practise the treatment, even if they have no or limited formal qualifications or experience
• these practitioners are not legally required to adhere to any standards of practice or to join an association or register

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 is acceptable to you.

Professional bodies and voluntary registers can help you to do this. See below.

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.

Professional associations and accredited registers for CAMs

Many CAMs have voluntary registers – some of which are accredited by the Professional Standards Authority for Health and Social Care (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:

• British Acupuncture Council
• Complementary & Natural Healthcare Council
• The Federation of Holistic Therapists

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.

Find more information on the PSA's accredited registers.

Questions to ask before starting a treatment

Once you've 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 for:

• the cost of treatment
• how long the treatment will last
• are there any people who should not use this treatment
• what side effects might the treatment cause
• is there anything you should do to prepare for treatment
• what system does the practitioner have for dealing with complaints about their treatment or service
• documentary proof of their qualifications
• documentary proof that they are a member of their professional association or voluntary register
• documentary proof that they are insured
• written references