You don’t hear the word “diathesis” much these days. It is one of those very quaint, 19th century sounding words that actually are a medical term, popular before the advent of modern medicine. Derived from the Greek word ‘diatithenai’, meaning ‘disposition’ or ‘condition’, it is used to describe an innate tendency to become ill in a certain way. The dictionary defines it as, “A hereditary predisposition of the body to a disease, a group of diseases, an allergy, or another disorder.”1 In old medical text, for instance, one can read about a ‘gouty diathesis’, a ‘gouty, rheumatic diathesis’, or a ‘uric acid diathesis’. These phrases indicate a disposition for certain persons to develop gout and rheumatic pains, generally because they have a tendency to build-up high levels of uric acid in their bodies.

All sorts of diathesis are found in the literature: tubercular diathesis, strumous diathesis (thyroid swelling), hemorrhagic diathesis, sthenic diathesis (excessive inflammation or reaction), scorbutic diathesis (scurvy), scrofulous diathesis (glandular swelling), lithic acid diathesis (kidney stones), … to name just a few.

Different people get sick in different ways, even if they have experienced a similar stressor. So, from a slightly different perspective, a diathesis indicates the type of susceptibility toward disease (‘morbid susceptibility’) a particular person has under conditions that are not optimal to maintaining health. The same stressor – whether physical or emotional – will cause different forms of illness in different people based on his or her diathesis.

Another similar term, especially favored by homeopaths, is ‘constitution’. And it would be reasonable to ask what is the difference is between the two. Generally, they can be thought of almost as parallel to each other: the ‘constitution’ referring to a characteristic way of being in the world and the diathesis a characteristic way of becoming ill.

Putting it another way, the constitution represents the overall characteristic state of health and vitality, physically and mentally, in a particular person while the diathesis represents the susceptibility a person with a particular constitution has toward illness. In fact, although it is not always the case, people with similar constitutions do tend to have similar types of illnesses. For instance, someone who homeopathically is a ‘phosphorus constitution’ (i.e. they fit the symptomatic picture and greatly benefit from a prescription of homeopathic phosphorus) will have a weakness in the respiratory tract.

Just to make things interesting, homeopaths also speak of ‘miasms’, a term that is similar to, but distinct from both ‘diathesis’ and ‘constitution’. Taken from the Greek word ‘miainein’ which means ‘to defile’, miasm is generally defined as, ‘an unwholesome atmosphere or a polluted atmosphere, ‘especially where there are noxious vapors from decomposing matter.’2

In homeopathy, miasms are understood to be underlying states resulting from an infecting agent. Long before the use of microscopes to identify the existence of micro-organisms and the development of the germ theory in medicine, the founder of homeopathy, Samuel Hahnemann, came to the conclusion that infection by ‘excessively minute, invisible living creatures’ was related to disease conditions.

To paraphrase Hahnemann, when a person falls ill, it is only through the dynamic influence of disease causing agents that are inimical to life that the vital energy of a person to becomes disturbed.

There are several interesting and important aspects to this miasmatic perspective. First, miasms can be both either acute or a chronic. That is, Hahnemann recognized that the measles, mumps, smallpox, plague and many other diseases were acute manifestations of invisible infection agent. But even more importantly, chronic disease or the disposition toward chronic illness was also due to miasmatic infection.

Secondly, he clearly stated that the influence of these infecting agents was ‘dynamic’ and not static. That is, the infecting agents can act energetically on the host creating an ongoing, active state in the body. Once this state was imparted to the host, a chronic condition is imparted and the removal of the agents themselves will no longer suffice to cure the disease.

Thus, we can now see that the miasm disposes the body toward a certain diathesis. That is, the chronic state imparted by the infecting agent makes a person susceptible to certain diseases. As an example, infection by mycobacterium tuberculosis disposes a person not only to develop tuberculosis acutely, but can also in the long term, dispose a person to chronic respiratory weakness and a host of respiratory illnesses.

As a result of a painstaking twelve-year period of research into the nature of chronic illness, Hahnemann also came to understand – several generations before the development of genetic theory - that both miasms and diatheses can be either inherited or acquired during one’s lifetime. So, using the above example, a history of one’s parents or grandparents having tuberculosis, very well will dispose a person toward a tubercular diathesis and a tendency toward respiratory illness.

1. American Heritage Dictionary of the English Language, 4th Edition 2000, Houghton Mifflin

2. Collins English Dictionary – Complete and Unabridged © HarperCollins


When I first began practicing homeopathy, my goal was relatively simple: take a full account of all the significant symptoms that the patient presented – physical, mental and emotional, and find the best medicine possible that matched those symptoms. To a large extent, some two decades later that is still my goal whenever I consult with a patient.

But one of the things that has changed is my understanding of what really is ‘significant’ in any given case. In particular, over the years it has become increasing evident that every person who presents with an illness has an underlying disposition, either inherited or acquired during his or her lifetime, to become sick in certain ways.

In homeopathy, the various types of dispositions are known as ‘diatheses’ and the underlying causes are generally referred to as ‘miasms’.

Let me give an example.

The first time I truly understood the significance of miasms and diatheses involved the case of a young girl who was brought by her mother many years ago with a diagnosis of idiopathic thrombocytopenic purpura (ITP), which is a bleeding disorder in which the immune system destroys platelets so that the blood can’t clot normally.

In many children, this condition spontaneously disappears after some time, but in this child it hadn’t. She bruised so easily and her skin was covered with purpura, rashes of purple spots on the skin caused by internal bleeding from small blood vessels. Untreated it can be a very dangerous condition. The child had been having regular blood transfusions and now her physicians were pressuring the mother to allow them to perform a bone marrow transplant.

Her mother wasn’t so keen on the idea. It was an incredibly invasive procedure and the rate of success wasn’t so great. She strongly believed there must be a better way to cure her child and, fortified by that belief, was able to resist the external pressures to conform to conventional approaches.

Even though the pathology was quite serious, homeopathically speaking, the case did not seem so complex. The child was a classic ‘type’, clearly displaying a ‘picture’ of the homeopathic medicine Phosphorus. The first thing you noticed were her glittering eyes, long lashes and thin physique. She had a bubbly, outgoing personality, made friends easily, was always popular with both adults and children, and had a natural sympathy for others. On top of that, one of the classic symptoms of Phosphorus patients is that they are easy bleeders: bruising, nose bleeds, or producing hemorrhages of just about any sort.

Over a number of months, the child made steady progress after beginning treatment with repeated doses of Phosphorus. The frequency of the transfusions decreased, and her overall energy as well as wellbeing improved. It seemed that, if we were patient enough, the entire condition might resolve.

But at a certain point, the progress reached a plateau. Around this same time, she also began to have fevers that needed to be dealt with on an acute basis. The fact that the case was not progressing coupled with the acute illness indicated that we had run up against an underlying issue that the current medicine was not addressing. It was as if we had hit a wall, and the child’s vital energies were calling out for a different remedy by throwing off these fevers.

Fortunately, the symptoms of the fever, which included night sweats and teeth grinding, clearly pointed toward another remedy closely associated with Phosphorus that directly addressed the child’s inherited disposition, that is, the miasm. A few doses of the Tuberculinum, a medicine derived from the bacilii of a tubercular abcess and which addressed her underlying tubercular inheritance, not only resolved the fevers but started to move the case forward once again.

Once this energetic obstacle was surmounted, it was possible to return to using the Phosphorus. Eventually, the condition totally resolved, the child went on to regain her health and remains healthy today.

Two centuries ago, when homeopathy was in its infancy, there were only 3 recognized miasms, each related to a particular disease and infective agent: scabies, syphilis and gonorrhea. Toward the end of the 19th century, homeopaths began to be aware that there was another inherited disposition in their patients, namely the tubercular miasm. This reflected the predominance of the disease starting several generations before.

By the mid-20thcentury, yet another miasm began to manifest in increasing numbers of person. Today, this fifth miasm - the cancer miasm – is perhaps the most common one. It shares a number of the symptoms of all 4 miasms that preceded it in addition to its own unique attributes.

Correspondingly, there are several different homeopathic remedies derived from malignant tissues that are commonly used by contemporary homeopaths. In fact, so frequent are the indications for these remedies found in modern day patients in the developed world, it is hard to imagine practicing homeopathy today without them.