Ayurved is an ancient science, it is not only a therapeutic science, and it is a science of life. Ayurved is a holistic science and is very near to nature. Ayurved prevents degeneration and destruction of health.

Ayurved plays an important role for the prevention and management of all the chronic diseases, including cancer by increasing the immune system.
Ayurved is based upon the fundamentals of Sankhya philosophy. According to this philosophy body is a result of integration of three constituents.

    [1]  The Sthul Sharir = the gross material body, consisting of gross state of matter. 
    [2]  Karan Sharir = the Jiwatma = the universal reality.

--- the livng sharir = the subtle body thus 18 constituents 

    [1]  Mahat = inteligence
    [2]  Ahankar = sence of self
    [3]  Manas = mind 
    [4]  Ten indriyas [ 5 Karmendriya = organs of action and 5 Gyanendriya = organs of sences ]
    [5] Panchtanmatra = 5 pre-atomic stages of the five states of matter.

The normal health of living beings is based on equilibrium of three ingoing nutrients, seven permanent tissues and three out going type of debris. These are known as Dhatus

The three nutrients charged with specific properties, are known as tri Dhatus, when they vitiated they are known as Tri Dosh, they are Vaata Pitta and Kapha .

Dhatus = seven permanent tissues are
 [1]  Rasa dhatu
 [2]  Rakta dhatu
 [3]  Mans dhatu
 [4]  Med dhatu 
 [5]  Asthi dhatu
 [6]  Majja dhatu 
 [7]  Shukra dhatu 

Three malas = type of debris are 
 [1] Pirish
 [2] Mutra
 [3] Sweda

The healthy status of thee constituents leads to health, the vitiation of any of them leads to ill-health.

The Tri Dosh in human embryo

- At the time of conception Tri Dosh are contained in the fertilized ovum and are delivered by a combination of the Soul = Jiwatma, and several elements from both the parents, in the foetus. When three layers are formed, the ectoderm of outer layer is predominantly made of Vaata type of cells, the mesoderm or the middle layer is made of Pitta type if cells and the endoderm or the inner layer is predominantly made of Kapha type of cells. 

The ectoderm contains the sensitive pains that develop in to the sense organs, including the skin and the whole nervous system may be known as Vaata layer.

The mesoderm is the precursor of the muscular, circulatory and other systems. This represents as it were the Pitta layer.

The endoderm is the precursor of the elementary canal, the respiratory system, mucus membranes and probably also lymphatic system. It may be known as the Kapha layer. 

When foetus develops, the tri Dosh are replenished from the matters circulation, and after birth through the milk, which represents SHAD RAS AHAR = food having six tastes.