Acupuncture The latest treatments to knock on the door of the establishment are acupuncture and herbal medicine.
A House of Lords report on complementary medicine recommended that these two should be regulated by law, and there are strong indications that this may eventually be extended to homeopathy too.
What's the attraction?
The increasing integration of mainstream and complementary medicine is primarily driven by patient demand, as more and more people 'vote with their feet' and choose complementary treatments.
It's certainly big business: complementary healthcare has an estimated annual turnover of some £1.6billion each year.
One in five of us uses complementary and alternative medicine (or CAM, as it is sometimes known), and there are an estimated 50,000 non-medical complementary practitioners, as well as a bewildering array of accreditation and registration bodies.
Doctors too, are getting more interested in complementary treatments. According to a BMA report, some 80 per cent of doctors would like to see acupuncture available on the NHS, and an estimated one in four Scottish GPs has had some homeopathic training.
GP practices currently report using CAM for a range of patients, including those with cancer, mental health problems and coronary heart disease. Hospital clinics are also using therapies such as massage and aromatherapy in cancer care and pain relief.
About the therapies
Osteopathy, chiropractic, acupuncture, homeopathy and herbal medicine are seen as the 'big five' and the ones for which doctors most frequently refer their patients.
Other therapies, such as aromatherapy, reflexology, massage and hypnotherapy, make up a smaller percentage of referrals, with a very small number made for treatments such as reiki and shiatsu.
However, popularity doesn't necessary correlate with scientific credibility. There is strong evidence, for example, that acupuncture is effective for a number of conditions, but the clinical evidence for the efficacy of homeopathy is more controversial.
Getting treatment on the NHS
Almost half of GP practices now offer some form of access to complementary medicine, either within the practice or via referral to an outside practitioner.
However, it's estimated that 42 per cent of treatments have to be paid for by patients themselves and that, overall, 90 per cent of complementary therapies are purchased privately.
There are five homeopathic NHS hospitals in the UK, and the British Medical Association says GPs have a duty to refer patients for homeopathic treatments within the NHS.
The Department of Health recommends that only those therapies that are statutorily regulated or have robust self-regulation should be made available through public funding.
The second part of our special report on complementary health therapies considers which fringe therapies are likely to join the healthcare establishment.
Osteopathy and acupuncture have joined the mainstream and other less well-known treatments are following in their wake, with some being used inside the NHS while others are gaining a fan base outside it. So which of the therapies that are 'bubbling under' will join the establishment, and which will go the way of phrenology and primal scream therapy?