According to him the external circumstances that immediately precede the diseases are only the exciting causes. The true cause is in the patient himself. This true cause of disease Hahneman called as Psora. All the diseases are only temporary out burst of psora.
Most people understand it to be itches or some kind of skin diseases, but it is not so, itches or skin diseases are not psora, but they are the effect of psora. Psora is the cause and itches and skin diseases are the effect .Psora is only a condition of the system that enables it to develop diseases.

History of the development of psora
So long as man lived strictly according to the law of God, so long as he thought, felt and willed, as he ought to have done as a creation of god, there was no trouble. But once he began to yield to false thinking and false willing and planning of God, violating the god’s law there begun a disorder in his mentation. This disorder in mind later reflected in physical body and this was the primary appearance of psora. It is from this disorder that man acquired the susceptibility to diseases. Initially there was only disorder in thought and this disorder in thought only made the disorder in action possible, because after thought come action. This bad action follows all the ills of man.
The bad thinking is almost similar to internal itching .This internal itching of the mind is the first requisite for all the human illness. This internal itching (bad thinking and bad willing) gradually cause some derangement in the external body, because external body is always in keeping with the internal mind. The external disorder in correspondence with the internal disorder is the manifestation of psora.
The first appearance of psora in the human body was in the shape of a kind of itch with exudation ,that is why people make the mistake of identifying psora with the itches and think that psora means itch. Itching is an unmistakable indication of psora.
Psora can be explained briefly as it is the condition pf the physical body, brought on by evil thinking and is the prime cause off all the varied illness of man kind. It is that acquired condition which is now inherent in human life force and which gives that life force the tendency for diseases. There are two other things beside the psora to make man ill, they are sycosis and syphilis. The system, which is not already psoric, cannot receive sycosis and syphilis because these originate from bad action (before bad action there must be bad thinking, ie psora)
The psora in itself is a cause for a hundred of disease, and when it combine with the other factors it become more destructive .The factors that make psora more destructive are
1) Allopathic treatment: suppressive treatment .Instead of freeing the patient from psora, they are pushing it more inward by strong medicines, especially by removing the external manifestation by external means.
2) Psora unites with sycosis and syphilis and it thus become ten times more destructive and mischievous
3) Unhomoeopthic homoeopathic treatment: Medicines given ignoring the fundamental laws of similarity, single medicine and minimum dose.
 
Sycosis
It is not gonorrhea, but it is that condition of the system which is bonded to it by the gonorrhea, when it is not cured but only to disappear either by a course of un homoeopathic treatment or by itself. Once the local infection is removed by UN homoeopathic treatment, the infection turns inwards and it then gradually attack the more internal organs and establishes sycosis. Finally it combines with psora and produces a complexity, which it become difficult for the system to be rid off.
The course of sycosis is naturally from the circumference to the center, from the body to the mind, from the gonorrheal discharge to colic to rheumatism to insanity.
 
Syphilis:
Like sycosis, syphilis is also acquired by cohabitation with a syphilitic woman. The primary manifestation id in the form of chancer, and if this is suppressed, the disease turn inwards and stamp syphilitic miasm inside.
The chronic miasms:
The miasms will always make themselves known by the character of their symptoms.
 
Symptoms of latent psora:
These 30symptpoms are not the expression of any particular diseased condition ,when these symptoms are there it is only to be understood that psora is there and it will some day break out in disastrous shape.
Cause of disease complication:
a)     allopathic and other suppressive method of treatment
b)    vaccination and injection
c)     Gradual fineness and subtlety of the miasms as also the knottiness of their bonds due to the progressive heredity.
d) Uniting of directly acquired miasms with these hereditary forms.
 
Psora:
Mind: -
- .Restlessness: -never satisfied with any thing. Restless in thought, feeling and will. This leads to restlessness in action.
- He is never satisfied with his wife seeks other woman, this ultimately end with contracting sycosis or syphilis.
- Psoric persons are intellectually keen but of no use to the world.
- Fearfulness - full of fears, fear of darkness, of being alone, of
Ordinary ailments, of physical work, of future.
Appetite:
- Unnatural appetite-comes at unusual hour, even immediately after a full meal, appetite never satisfied
·        sweats while eating, abdomen full of wind immediately after
eating
·        Sleepiness after a meal, he cannot do with out an actual sleep.
·        Likes sweet and sour things
·        Likes those food which will do harm
• Unnatural craving -chalk, slates. pencil etc,
- Females develop their characteristic trait during pregnancy
- prefer fried things rather than boiled things
- Aversion to meat
- Prefer food and drinks warm.

Head:
- < & > with course of sun
- > from rest, application of heat and from sleep
Canine hunger before headache
- Itching dandruff after long lasting ailment with falling of hair
- Premature graying in head and other parts
- Prefer head uncovered
Eyes:
-<&> with sun> warmth
Itching and burning, tendency to rub the eyelids.

Ear:
Psora seldom manifest in ear
Sensitiveness - an unbearable ness of noise and sound.
Psora alone cannot work much mischief to the ear and eye beyond an unusual sensitiveness which is a disorder of function.

Nose:
Accentuated power of smell, unbearable ness of smell of food or of cooking and consequent vomiting, this often causes vertigo and dislike for food.
Mouth:
Sour, bitter or sweet taste

Abdomen:
Wind, rumbling, hunger-before midway in the morning, during sleep, before headache, sour eructation, eructation tasting the food taken, sense pf emptiness in stomach or in other parts.

Respiratory:
Has not much cold and cough. Psoric cold and cough are never fatal, but the patient is very anxious over a little cold.
When complicated with syphilis leads to tubercular condition. Patient gets fatal cough and cold but the patient is not anxious, he has the hope of survival. They think that there is not much the matter with them

Heart:
Anxieties even with slight pain and palpitation, anxiety beyond all proportion
Anxiety alone will often indicate psora, and point out that there is no other miasm predominant.
 
The two important characteristic of psora are
1) Sensitiveness,
2) Want of structural changes- there are no structural change in psora and if there is any, there is one or both the other miasm –syphilis or sycosis

There are two condition necessary for structural change
a)     time &
b)     Sycosis or syphilis or both against a psoric background.
 
Sycosis:
Of all the miasm psora is the most wide spread but sycosis is the most insidious and dangerous
ØMind:
A peculiar tendency for making a secret of every thing
Anxious that his secret will be revealed
He thinks that others are also of the same mentality and are trying to keep things from him and this causes suspiciousness
          -changes the doctor frequently-e think that he hadn’t expressed his symptom clearly
-if he writes some thing, he would read it over again and again and make changes every time, suspecting that the idea hasn’t correctly laid in it.
Tendency for brooding over things.
Sycosis make the person devoid of all sense of righteousness, it make him a liar and vicious scoundrel, makes him destitute of all love and affection for others, male him mean and selfish.
All the vicious individuals –thieves, robbers and murderess are the product of sycosis. It makes a beast out of a man.
Memory –weaker and weaker, particularly for name and dates
Sycosis mainly affects affection and memory
Sycosis mentally is suspicious, mischievous, mean, and selfish and forgetful.
 
ØPhysical:
Condylomatous growth of various sizes and colors, some like cauliflower some exude an offensive discharge.
All kinds of tumors and tumoroid growth are sycotic
Any unusual fleshy growth in any part is sycotic
Irritable temper, extremly irritable worse on the approach of or during a storm or rain
Frequent urination <approach of a storm or rain –living barometer
Desire to move about, during rain and storm
While writing or speaking the sycotic is unable to decide which would be the appropriate word –slowness in speaking and writing .But in psoric when he writes or speaks, he does it very quickly, there is rapid flow of thought that he can hardly follow with his tongue or pen
Inflammation of the testis,hydrocele,orchitis, rheumatism,cold and catarrh in any part of the body ,anaemia, emaciation on any part of the body ,all urinary troubles –DM,haematuria
All uterine and ovarian troubles are sycotic
Teething troubles of children, sweating of the head, sour diarrhea and infantile cholera are sycotic.