A system of medicine in which a substance that can make people ill is diluted thousands of times to treat the symptoms it would otherwise create.

A basic principle of homoeopathy is that of “like cures like”. Symptoms of disease are considered indications that our health maintenance systems have failed and the body is fighting infection. Rather than suppressing symptoms, homoeopathic practitioners try to stimulate natural healing processes with substances that, in normal doses, would have the same effects.

For example, belladonna (deadly nightshade) causes flushing, dry mouth and throat, raging fever and convulsions (and ultimately death). Homoeopaths use a high dilution of the plant extract to treat conditions such as throbbing headaches, coughing spasms, high temperature and twitching during sleep.

The energy that regulates a healthy balance in the body is known in homoeopathy as the “vital force”. Stress, inadequate diet, lack of exercise, hereditary problems or environmental factors can disrupt this process, resulting in illness.

In common with many complementary therapies, this approach is based on theories about how illness relates to the whole person, physically and psychologically, rather than just a single “diseased part”.

Another basic principle of homoeopathy, and the one that arouses most controversy in orthodox medicine because it defies known science, is that of the “minimum dose”. Substances are diluted thousands of times over until there is no detectable trace of the original.

Homoeopathic practitioners believe that the greater the dilution, the more “potent” the remedy. Dilutions begin with a mother tincture: one drop of a substance dissolved in a mixture of 90 per cent pure alcohol and 10 per cent distilled water. Most homoeopathic remedies are derived from plants or minerals — Rhus tox from poison ivy, Natrum mur from salt — but some are “nosodes”, remedies made from diseased tissues or bodily secretions.

The recent anthrax scare caused a run in homoeopathic pharmacies on Anthracinum, a nosode derived from the spleen of an anthrax-infected sheep.

Remedies are “potentised” by dilution either on the decimal scale (1:10, denoted x) or the centesimal scale (1:100, denoted c). To produce a 12c remedy, for example, one drop of the mother tincture is added to 99 drops of an alcohol/water mixture and “succussed”, or shaken vigorously, and this procedure is repeated 12 times. A 30c remedy is diluted and succussed 30 times. The most “potent” remedies of all are 200c, 1,000c, or even higher, at which point not even a molecule of the original substance is likely to be left.

Homoeopaths maintain that a “memory” of the active substance is imprinted on the water molecules, which is capable of stimulating self-healing processes through some, as yet undiscovered, mechanism.

Non-medical homoeopaths often talk about “vibrational energy”, whereas homoeopathic doctors prefer to use terms from quantum physics.

The Faculty of Homoeopathy

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