The mother of medical sciences of the world-the knowledge came directly from God Brahma. The Ayurvedic classical texts were written in India between 3,500 and 5,000 years ago. Ayurveda draws its origin to Ayush (Life) and Veda (Knowledge) so Ayurveda is a science of life. According to CharakaSamhita, Ayurveda lays down the good and bad of life, the happy and unhappy life and what is wholesome and what is unwholesome in relation to life, as also the span of life. It is an ancient medical science. It helps to keep fit. It provides cure using indigenous plants, animal products and minerals for ailments. It is a science of living healthy life. It deals with normal as well as abnormal body. It deals with both preventive as well as curative aspects of medicines.
Ayurveda-The complete knowledge for long life.In Sanskrit, the word ayurveda consists of the words āyus, meaning "Longevity", and veda, meaning "related to knowledge" or "Science".
Ayurveda is a science of life so to know more about it, we must know what is life? Life according to Ayurveda is a combination of senses, mind, body and soul. So it is clear from this definition of life that Ayurveda is not only limited to body or physical symptoms but also gives a comprehensive knowledge about spiritual, mental and social health.
Ayurveda provides reference points for managing treatment decisions specific to each case. Ayurvedictheory is profoundly useful in analyzing individual patient constitution and understanding variations in disease manifestation.
Ayurveda provides specific Do's and Don'ts to each individual on lifestyle, diet, exercise and yoga, herb therapy, and even spiritual practices to restore and maintain balance in body and mind. This understanding that we are all unique individuals enables Ayurveda to address not only specific health concerns but also provides explanation as to why one person responds differently than another.
All matter is thought to hecomposed of five basic elements (Panchamahabhutas) which exhibit the properties of earth (Prithvi), water (Jala), fire (Tejas), wind (Vayu) and space (Akasha). These elements do not exist in isolated forms, but always in a combination, in which one or more elements dominate. According to Ayurveda, the human body is composed of derivatives of these five basic elements, in the form of doshas, tissues (Dhatus) and waste products (Malas).

TRIDOSHA

The most fundamental and characteristic principle of Ayurveda is called "Tridosha" or the Three Humours. Doshas are the physiological factors of the body. They are to be seen as all pervasive, subtle entities, and are categorized into vata, pitta and kapha.
Vataregulates movement and is represented by the nervous system.
Pitta is the principle of biotransformation and is the cause of all metabolic processes in the body.
Kapha is the principle of cohesion and functions through the body fluids.
Together, these three doshas determine the physiologic constitution of an individual.Health is described as a balance of all three doshas(Bodily Humours).

DHATU

The tissues are classified into seven categories: Rasa (Plasma), Rakta (Blood Cells), Mansa (Muscular tissue), Meda (Adipose tissue), Asthi (Bony tissue), Majja (Bone marrow) and the Shukra (Reproductive tissue).

MALA

Three main waste products are Mutra (urine), Purish (faeces) and Sweda (sweat).

AMA

Ama is immature Rasa caused by diminished agni prone to produce pathological syndromes. It is in fact, endotoxin produced by incomplete digestion or transformation of edibles or metabolites due to diminished agni at respective levels. Ama associates in the process of pathogenesis by combining with dosa and dusya and exhibits its characteristic symptoms.

AGNI

Agni is the invariable agent in the process of paka (Digestion, Transformation). They are thirteen in number-jatharagni (Gastric fire) one, bhutagni five and dhatvagni seven. Of them the gastric fire known as Vaisvanara (Present in all living beings) is the most important one which digests the four types of food and transforms it into rasa and mala. The five bhutagnis act upon the respective bhautika portions of food and thereby nourish the bhutas in the body. The seven dhatvagnis act upon the respective dhatus by which each dhatu is broken in three parts-the gross part becomes as mala, the fine part stays as itself and the finer one goes on in formation of the successive dhatu.

SROTAS

The channels in the form of tracts, veins, arteries etc. are known as srotas which are also called as ‘Kha’ (Akasa=empty space). They carry and transport four types of food, dhatus, dosas and malas. Dhatu sustains the body and nourishes the successive dhatu only when digested fully by its agni and transported properly through its channel. Thus srotas play important role in dhatupaka (metabolism).

PANCH MAHABHOOT

Purusa (Person-the living being), in Ayurveda, is regarded as composed of six components-five mahabhutas (Matter) and self10 (Spirit). The gross human body along with its different organs and parts, the sense organs and the sense objects are all composed of five mahabhutas, e.g. akasa, vayu, agni, ap and prthivi. The outer universe also has the same material composition and thus there is similarity between it and the material frame and skeleton of the living being.

OJAS

It is mentioned as the essence of all the dhatus emanating after sukra.It is neither dhatu nor upadhatu but has independent position. It is seated in hrdaya and is intimately connected with prana. In absence of ojas no living being can survive. It supports strength and lustre and is the basic factor of general immunity. Ojas maintains the tone of heart as well as brain.When ojas is diminished the natural power of immunity (Resistance) goes down and as such the person falls prey to a number of ailments. AIDS is a typical example where the man suffers from ojahksaya (Diminution of ojas) and consequent disorders leading to death.

RASA

Rasa is perceived by the gustatory sense organ and is essentially watery though other mahabhutas also participate in manifestation of different types. Rasas are six in number-madhura (Sweet), amla (Sour), lavana (Salty), katu (Pungent), tikta (Bitter) and kasaya (Astringent).

"SAMPRAPTI-The Disease Process(Pathology)&Chikitsa-(Treatment of Disease)."

Under normal conditions, the doshas, dhatus and malascorrespond to certain standards regarding their quantity, quality and function. However, this situation is not static, and due to several endogenous and exogenous factors, the doshas may become unbalanced, resulting in disease. Every disease is related to an imbalance of the doshas. Other coherent factors can be the disturbance of the biological factors (Agnis). The formation and collection of undigested nutrients (AMA). Obstruction of the body channels (Shrotorodha), and a disturbed assimilation in the tissues. Chikitsa, Disease Management (Pharmacology and Treatment) There are four main classifications of management of disease in Ayurvedashodan or cleansing; shaman or palliation; rasayana or rejuvenation; and satvajaya or mental hygiene. Ayurveda gives us a model to look at each individual as a unique makeup of the three doshas (Prakruti) and thereby design treatment protocols that specifically address a persons health challenges. When any of the doshas(Vata, Pitta or Kapha ) become imbalance, Ayurveda will suggest specific lifestyle and nutritional guidelines to assist the individual in reducing or increasing the doshas that has become imbalance. The ingredients used in Ayurveda are made by several processes from vegetable and mineral raw materials. Mostly plant alkaloids are the active ingredients. Obviously barring some chemical changes it is mostly natural deviates.