Discover Homeopathy

The science and evidence base for homeopathy


Homeopathy was invented by Samuel Hahnemann, 1755-1843. Hahnemann studied medicine, graduating from the University of Erlangen in 1779.

18th century medicine

In Hahnemann’s time, medicine was still largely based on a model that had first been described more than two thousand years earlier in Ancient Greece. According to this ancient theory — usually referred to as ‘vitalism’ — disease was the result of a disturbance of metaphysical vital forces caused by an imbalance in the four bodily ‘humours’ or liquids: phlegm, blood, gall and choler. When Hahnemann was studying medicine, doctors were prescribing remedies made from mercury and arsenic and inflicting barbaric treatments on patients in their attempts to ‘restore the humoural balance’ believed to be necessary for sound mental and physical health. These included purging, leeching and bloodletting — treatments that had been used for thousands of years because people believed they were effective. That some patients recovered in spite of treatments like bloodletting was perceived as evidence of efficacy.

Similia similibus curentor or ‘like treats like’

Hahnemann didn’t care for much of what passed for modern medicine and believed that large doses and combinations of drugs and practices like bloodletting were dangerous and unnecessary. The idea of developing homeopathy as an alternative system of medicine grew out of some research Hahnemann carried out in the 1790s, beginning with a consideration of the effects of chinchona bark. The bark contains quinine, which has antipyretic, antimalarial, analgesic and anti-inflammatory properties. The powdered bark had been used for the treatment of malaria for at least two centuries, though the reasons for its apparent efficacy were a matter of speculation. Hahnemann applied himself to this question and conducted an experiment on himself by ingesting some chinchona bark and noting his unusual symptoms.

I took by way of experiment, twice a day, four drams of good China [Cinchona]. My feet, finger ends, etc., at first became cold; I grew languid and drowsy, then my heart began to palpitate, and my pulse grew hard and small; intolerable anxiety, trembling, prostration, throughout all my limbs; then pulsation in the head, redness of my cheeks, thirst, and in short, all these symptoms which are ordinarily characteristic of intermittent fever, made their appearance, one after the other, yet without the peculiar chilly, shivering rigor, briefly, even those symptoms which are of regular occurrence and especially characteristic — as the dullness of mind, the kind of rigidity in all the limbs, but above all the numb, disagreeable sensation, which seems to have its seed in the periosteum, over every bone in the body — all these made their appearance. This paroxysm lasted two or three hours each time, and recurred if I repeated this dose, not otherwise; I discontinued it, and was in good health.1

Hahnemann, knowing that chinchona bark was used to treat malaria, decided that the symptoms he’d suffered after ingesting some of the bark were close enough to those of malaria to hypothesise that a substance that causes particular symptoms in a well person can relieve similar symptoms that are manifestations of sickness.
Many of Hahnemann’s experiments involved herb extracts, which were already known to have medicinal effects. Hanemann’s volunteers knew what remedies they were taking and what effects to expect.[/pullquote] Hahnemann conducted further experiments on himself and on volunteers who were drawn from male members of his family. As time went by, his ideas began to excite interest and he was able to find volunteers from amongst his disciples. He called these experiments ‘provings’; they involved ingesting various substances and keeping detailed records of any perceived effects. He decided that his observations confirmed the hypothesis that ‘like treats like’.

Smaller doses

It is widely believed that Hahnemann used high dilutions for these experiments but in fact he used material doses similar to those used by orthodox physicians at the time. Some of the substances investigated were poisonous and had extremely unpleasant long-term effects on the ‘provers’. Reports included spongy gums, decaying teeth, loss of facial hair including eyebrows and paralysis of limbs.2 Hahnemann soon switched to suggesting tiny doses in order to reduce the unwanted effects of the substance. There is nothing to suggest that, at this stage, he thought reducing the dose would make the medicine more effective. In fact he pointed out that diluting the medicines did not appear to weaken them as much as expected. He also claimed that sick people were more sensitive to medicine so needed smaller doses.2 The notion that the smaller the dose, the more ‘potent’ it becomes, is one that developed gradually over a number of years (and one that damaged Hahnemann’s credibility in the eyes of some who had hitherto supported him).


While devotees of homeopathy are inclined to take the story of its origins at face value, critics point out a number of problems. Most importantly, Hahnemann didn’t take into account the power of suggestion. Many of his experiments involved herb extracts, which were already known to have medicinal effects. In his experiments, his volunteers knew what remedies they were taking and what effects to expect. Furthermore, they knew each other and were free to discuss their symptoms.2

The amount of quinine Hahnemann ingested is said to be 400-500 mls, which was a normal therapeutic dose and which millions of people have taken without ill effect. Whether the symptoms he described did indeed match those of malaria is disputed, with a hypersensitivity to quinine being offered as a more plausible explanation.3 Another hypothesis is that he what he described was the Herxheimer Reaction.4

Major works

In Hahnemann’s essay of 1806, The Medicine of Experience, he set out the following as the fundamental principles of homeopathy:

  • Medicines are to be chosen on the basis of the patient’s symptoms without reference to whatever is believed to be the disease process underlying them.
  • Effects of drugs can only be known by means of experiments on healthy people so as not to confuse them with symptoms of any disease suffered in sick people;
  • Medicines must be chosen for the similarity of their effects to the symptoms of the patient;
  • Medicines are to be given in single doses rather than complex mixtures;
  • Medicines are to be given in small doses to prevent aggravations;
  • Medicines are to be repeated only when recurrence of the patient’s symptoms indicates the need.

While some of these principles may seem absurd in light of modern scientific knowledge, at the time they were a much safer way to treat patients than most mainstream medical procedures of the early 19th century. Thus they attracted quite a bit of interest and, for Hahnemann, a small band of devoted followers. In 1810, Hahnemann published the first edition of his Organon of Medicine (as it was eventually renamed). The sixth and final edition of the Organon was published in 1821. In 1811, he published the first of six volumes of his Materia Medica Pura, which is a compilation of all the reports of the ‘provings’ carried out by his volunteers and much of the information it contains forms the basis of homeopathy today. However, as Hahnemann recorded this information according to a scheme that he devised himself and one that is largely incomprehensible to everyone else, few homeopaths refer to it directly.2 The sixth volume was published in 1827, the first two volumes were revised in the 1830s. The following year he published his last significant work: The Chronic Diseases, their Peculiar Nature and their Homœopathic Cure. This didn’t sell well and there were only two editions.


The six editions of the Organon reflect a gradual shift in Hahnemann’s ideas to a more spiritual approach and an increasing sympathy with the concept of vitalism, which still held sway in Hahnemann’s lifetime, although Hahnemann himself had initially been dismissive of it.2 Hahnemann used the word ‘dynamis’ interchangeably with the term ‘vital force’ to refer to the mysterious power that gives life to the body and governs our physical and mental well-being.

The organism is indeed the material instrument of the life, but it is not conceivable without the animation imparted to it by the instinctively perceiving and regulating dynamis, just as the vital force is not conceivable without the organism, consequently the two together constitute a unity, although in thought our mind separates this unity into two distinct conceptions for the sake of easy comprehension.4

And, in keeping with the pre-science beliefs of ancient physicians, for Hahnemann it was the disturbance of this vital force that caused illness.

When a person falls ill, it is only this spiritual, self acting (automatic) vital force, everywhere present in his organism, that is primarily deranged by the dynamic influence upon it of a morbific agent inimical to life; it is only the vital force, deranged to such an abnormal state, that can furnish the organism with its disagreeable sensations, and incline it to the irregular processes which we call disease;5

Potencies and potentization

While the suggestion that the more a substance is diluted, the more potent it becomes, is clearly wrong, Hahnemann became convinced through his own experiments that this could indeed happen, provided that the medicine was selected according to homeopathic principles. He reasoned that the more liquid added to a medicine, the further it will reach without any diminution of its powers.

…the effect of a homœopathic dose of medicine increases, the greater the quantity of fluid in which it is dissolved when administered to the patient, although the actual amount of medicine it contains remains the same. For in this case, when the medicine is taken, it comes in contact with a much larger surface of sensitive nerves responsive to the medicinal action. Although theorists may imagine there should be a weakening of the action of dose of medicine by its dilution with a large quantity of liquid, experience asserts exactly the opposite, at all events when the medicines are employed homœopathically.4

(‘Employed homeopathically’ means ‘used according to Hahnemann’s Law of Similars’, not ‘greatly diluted’.) Hahnemann further argued that the original medicinal ingredient is rendered effective through the process of ‘potentization’ (also called ‘dynamization’):

…by which simple operations the powers which in their crude state lay hidden and, as it were, dormant, are developed and roused into activity to an incredible extent.34

Potentisation is a ritual that involves serial dilutions of the ‘mother tincture’ , which is the original ingredient dissolved in water or alcohol. Each dilution is interspersed with shaking the diluted remedy a set number of times (‘succussion’). This process, Hahnemann believed, releases the astonishing power of the original ingredient which, thus dynamised, can now work with the body’s vital force to rid it of natural disease process.

As every disease (not entirely surgical) consists only in a special, morbid, dynamic alteration of our vital energy (of the principle of life) manifested in sensation and motion, so in every homœopathic cure this principle of life dynamically altered by natural disease is seized through the administration of medicinal potency selected exactly according to symptom-similarity by a somewhat stronger, similar artificial disease-manifestation. By this the feeling of the natural (weaker) dynamic disease-manifestation ceases and disappears. This disease-manifestation no longer exists for the principle of life which is now occupied and governed merely by the stronger, artificial disease-manifestation. This artificial disease-manifestation has soon spent its force and leaves the patient free from disease, cured. The dynamis, thus freed, can now continue to carry life on in health.3

Miasms and Chronic Disease

Miasma theory can be traced to Ancient Greece and was still widely believed by practitioners of orthodox medicine in Hahnemann’s time. A ‘miasma’ was a term used to describe the ‘bad air’ or noxious vapours that were believed to cause disease.

Hahnemann was satisfied that his homeopathic remedies were effective for acute conditions but when trying to treat chronic conditions he found that, while remedies often appeared to work initially, symptoms often returned or new symptoms developed. By way of explanation, Hahnemann devised a very contentious theory that most chronic disease is caused by a ‘miasm’ invading the body through the skin, the most significant misam being the ‘psora’ which, Hahnemann decided, accounted for most chronic disease.

He theorised that the first sign of bodily invasion by a miasm was a rash or other skin disorder. This might clear up with or without treatment and the patient may well forget all about it. But the miasm, having now taken up residence in the body, continues to spread and causes any number of health problems over the years. Thus, in Hahnemann’s eyes, he was able to preserve the inviolability of his system by postulating the existence of a cause of disease that was deep-seated and almost eradicable.2

He presented this doctrine in his 1928 publication on Chronic Diseases. Amongst his supporters, it wasn’t universally well-received and continues to be a bone of contention among homeopaths today.






1. Cullen, W.: ‘Abhandlung uber die Materia Medica. Ubersetzt und mit Anmerkungen versehen von Samuel Hahnemann.’ 1790
2. Anthony Campbell, Homeopathy in Perspective
3. Dr William.E.Thomas MD
4. Gabe Mirkin, M.D.
5. Hahnemann’s Organon of Medicine, sixth edition
6. Hahnemann’s Organon of Medicine, fifth edition