Hypnosis works by creating a state of altered awareness in the person being hypnotised. The idea is that this calms and partly switches off the conscious mind leaving the subconscious open to receive suggestions and ideas that might remove fears or tensions and improve wellbeing.

Hypnosis formed part of the medicine of the ancient Greeks but was developed and refined in the twentieth century by the Austrian physician Franz Mesmer (who gave his name to mesmerism).

There are many different ways of hypnotising people but the commonest involves simply lying or sitting comfortably in a quiet semi-darkened room whilst the hypnotist talks in a soothing, calming voice about things which are intended to produce a sense of peace and tranquillity. Once the hypnotherapist feels that the right state of altered awareness has been reached they can then suggest ideas and thoughts intended to help with the particular problem that needs to be treated.

The idea that a hypnotists can make people do things they do not want to whilst they are hypnotised is an old wives tale and quite untrue. Hypnotism does need the co-operation of the person being hypnotised and even then there are some people for whom it just doesn't work, however motivated they are for it to be successful.

Hypnotism can be very helpful in dealing with problems like giving up smoking, fears about flying, bedwetting and easing anxiety and stress.

There is no suggestion that hypnosis can actually help prevent, treat or cure cancer. But there is evidence that people with cancer who have hypnosis may find it helps in coping with the side-effects of treatments like chemotherapy and also reduces the worry and stress associated with their illness, helping them to cope better and have a better quality of life. Hypnosis may also help reduce pain associated with cancer and there is some evidence that it can increase the activity of the body's immune system, which would be a good thing for people with cancer.

If the hypnosis is done by a trained hypnotherapist then there are really no dangers with the treatment and, for some people, it can prove a helpful addition to conventional therapies, like radiotherapy and chemotherapy, in managing their cancer.