Dr. Samuel Hahnemann classified disease into four great divisions in order to establish logical basis for the recognition of disease conditions and to know their origin and relationship.

• Diseases due to Mechanical or External sources
  

  These include fractures, strains, faulty diet, poisoning, and exposure to extremes of heat or cold like frostbite and sunstroke. These diseases may be caused by some mechanical means. They are mainly self-curative, or can be set right by regulating environmental or style of living. Medicines can be used to assist or hasten the process of recovery. Removal of the causative factor if still persists is the first procedure to be followed for cure. It may involve surgical procedure or rectifying the diet or removal of irritating substance.

• Diseases due to Indisposition
  

  These diseases arise due to presence of the maintaining cause (Causa Occasionalis). The maintaining causes are the causative factors, which maintain the disease. These may be in the form of continuous exposure to strong odor, presence of foreign body which excites inflammation (Vesicles, foreign bodies in orifices of body), improper hygiene, bad sanitation, living in a damp or poor ventilated house, irregular improper diet, and lack of exercise. These diseases are extinguished only when the above causative factors are removed, surgically or by change in life style. Usually they do not require medicinal aid except in situation where the underlying miasm is affected due to prolong stimuli.

• Acute Diseases
  

  Acute diseases are the result of rapid morbid process of the deranged vital force. Their onset is sudden, have definite and quick course of action and disappear within a short time. They either terminate in death or recovery. Acute diseases can again be classified into four groups.

  • Those that attack individually: These acute diseases attack human beings individually. Exposures to extremes of temperature, to storms, mental emotions are usually the exciting causes in these cases. There is transient explosion of latent Psora, which soon returns to its dormant state after the individual is relieved of his sufferings.

  • Those that attack Sporadically: These acute diseases attack several persons at same time here and there due to the climatic or telluric influences and injurious agents. In this case the susceptibility is morbidly affected in few persons at one time.

  • Those that attack Epidemically: Here many persons are attacked with very similar sufferings from the same cause. These diseases usually become infectious when they prevail among thickly populated regions. Poor sanitation at large gathering like fairs, wars and natural calamities like earthquakes and famines excite them. Some types, which are caused by Acute Miasms, attack persons once in lifetime. Eg. Mumps, Measles, Whooping Cough, etc.

  • Those that are Endemic: Here the diseases continuously prevail in a community all the time attacking many persons with similar sufferings from the same cause. These diseases are usually infectious.

• Chronic Diseases:
  

  These diseases have imperceptible beginning, dynamically derange the living organism in their own peculiar manner resulting in gradual deviation of health. The vital force hardly resists its action and progress, and suffers with further derangement till the living organism is fully destroyed. The chronic diseases are caused by the chronic miasms Psora, Syphilis and Sycosis.

  Chronic Diseases can again be classified in following types,

  • With good number of symptoms:In this type good number of symptoms are displayed to the observing physician. These are good cases to treat as there are handy symptoms to select the similimum.

  • One-sided diseases: Diseases having few symptoms, hence less amenable to cure. They only display one or two principal symptoms, which obscure almost all others. These are most difficult diseases to treat as there is scarcity of symptoms. These include mental diseases also. The principal symptom may be either and internal complaint like headache, diarrhoea of long standing, or it may be an affection more of an external kind, termed as Local Maladies wherein the changes and ailments appear on the external parts of the body (e.g. Skin diseases).

  • Intermittent Diseases: These diseases recur at certain intervals where a morbid state of unvarying character returns at a fixed period, whilst the patient is apparently in good health during intervals, and takes its departure at an equally fixed period.

  • Alternating Diseases: In these diseases a morbid states alternate at uncertain intervals with morbid states of a different kind.

• Artificial Chronic Diseases:

  These diseases originate by prolonged use of violent and large doses of medicines wherein the vital force is weakened to a large extent producing faulty organic alterations in the body in order to prevent the body from total destruction.