Whether yoga causes an enlightened mystical state or simply cramp depends on the individual, but it is officially the most popular complementary therapy. With celebrity followers including Geri Halliwell and Trudi Styler, Sting's wife, the Eastern discipline has been given plenty of publicity.

A survey by Which? shows yoga's results. Some 82 per cent of the 1,198 people in the survey said it had helped them. Reflexology was the second most-popular therapy, with a 72 per cent rating. Herbal medicine was at the bottom with only 45 per cent of customers satisfied.

"Generally, people in our survey were satisfied with the complementary therapies they used," Helen Parker, Which? editor, said. "Those practising yoga or having reflexology were most satisfied with the therapies, but chiropractic and osteopathy came top as therapies which yielded the greatest health improvements when it came to back and neck problems." Customer satisfaction with complementary therapies seemed to hinge on whether a qualified practitioner was consulted. Sixty-seven per cent who did so were happy with their treatments, but 55 per cent did not.

Jayne Goddard, president of the Complementary Medical Association, a self-regulating body for the industry, said that may have caused the low rating for herbal medicine. "I'm absolutely amazed at the low percentage. I don't believe herbal remedies should be available over the counter. Most of the time people aren't happy because they are taking the wrong remedies."

Finding the right practitioner for therapies can be confusing because the General Osteopathic Council and the General Chiropractic are the only regulatory bodies approved by the Government. Therapists offering other services who have been struck off their register can continue to practise, and the Consumers' Association advises people to check for relevant qualifications, ask about experience and choose through personal recommendation to ensure satisfactory service. A spokes-woman for the association said: "We're very concerned about this. The two bodies that are regulated go through a fairly rigorous process to practise."

Three-quarters of those surveyed used a complementary therapy to treat a specific illness or condition, while for the rest it was general wellbeing. Most paid for complementary medicine, with just 5 per cent being referred by the NHS, and a similar proportion on private health insurance.

Of all the varieties of yoga, Hatha has become the most popular in Britain. But there are reports of a growing number of injuries linked to the trend for more vigorous forms, such as ashtanga. Ms Styler, who runs a film production company, recently snapped her sternum during an ashtanga workout.