The placebo effect happens when a person takes a medication or receives a treatment and perceives that it has relieved their suffering even though it has no proven therapeutic effect for the condition.

Many placebos are just sugar filled pills, yet they have been shown to help in about 30 per cent of patients with significant impacts seen in chronic back pain, irritable bowel syndrome, episodic migraines and rhinitis.

We still don't know how placebos work, but some researchers believe that they evoke a psychological and in turn a physical response where the act of taking a pill gives you a positive sense of well-being.

Although placebos have been known to help patients, the assumption has been that placebos only work when the patient believes that they are being given a real treatment leaving the doctor with an ethical decision of whether or not to deceive their patients into taking something they know has no active ingredients.

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This week new research published in the journal Pain may help with this dilemma and remove the need for doctors to lie to their patients to try and help them.

The experiment took 160 volunteers aged between 18 and 65 and asked them to put their arm on a heating plate to form a minor burn. The volunteers were then split into four groups with different aftercare treatment.

The first group was given a placebo cream; however, they were told that they had been prescribed a burn treatment cream containing the topical painkiller lidocaine to help reduce the pain of the burn. They were given information about the effectiveness of the cream and how it was proven in several high-quality studies.

The second group was given a placebo cream and told that it contained no active ingredients. They were then given a 15-minute talk explaining the meaning of the placebo effect using evidence where it had been found to alleviate symptoms of pain in Parkinson's disease, asthma, migraines and depression.

They were taught about how the body can self-heal using placebos in the same way that Pavlov's dogs physically salivated when they heard a bell and were told that a positive attitude could be helpful for the efficiency of placebos.

The third group was given a placebo cream and told that their cream was an inert substance and did not contain any pharmacological ingredients.

The fourth group was not given and aftercare and acted as a control group.

The groups were then asked to describe how they felt after receiving their treatments.

Those patients who thought they received lidocaine and who heard the placebo explanation talk reported positive benefits from their creams and recorded that their burn unpleasantness had reduced after using the cream even though neither cream contained any medicine.

In contrast, the group that knew they were receiving a placebo cream with no explanation were left in uncomfortable pain to the same extent of the no-treatment control group.

Although I never want to volunteer for a study where you have to burn your arm, I'm glad 160 other people did as this study suggests that the placebo effect can still be useful even when patients are told about it, as long as they are also given an explanation about how it might bring benefits.

These results go against previous thoughts that placebo pills only worked when patients were deceived into thinking they were taking an active ingredient for it to work.

Thanks to some brave volunteers, this research could open up options for doctors to openly prescribe sugar pills with the potential to relieve suffering in an ethically justifiable way.

Dr Michelle Dickinson, also known as Nanogirl, is an Auckland University nanotechnologist who is passionate about getting Kiwis hooked on science. Tweet her your science questions @medickinson.