Ayurveda is a Sanskrit word made up of two words AYU and VEDA, Ayu means Life and Veda means Knowledge hence the word Ayurveda means Knowledge of life. It is not only a medical science dealing with the disease and diseased but Ayurveda is the knowledge which helps a person to live a happy, satisfied, useful and long life.
The origin of Ayurveda is believed to be untraceable and Charak Samhita, one of the most important texts of Ayurveda mentioned that Ayurveda is eternal as it has no beginning. The oldest written storehouse of all types of knowledge is Vedas, the four texts containing divine knowledge of all living and non living things of the nature. These are Rigveda, Yajurveda, Samveda and Atharveda. Out of these Atharveda contain many references to the health, diseases and their treatments. Ayurveda is called as Upveda or a part of Atharveda. Ayurveda is also a divine knowledge which was learnt by our sages who were worried and perturbed by the plight of human beings suffering from various diseases. While describing the spread of knowledge of Ayurveda, in Charak Samhita it is mentioned that Lord Brahma taught the sacred science of healing to Daksha Prajapati, who in turn taught it to gods, from where the light of Ayurveda traveled to Bhardwaj Rishi, a renowned Sage having a deep urge to make people of this earth free of pain and misery of diseases. This way Ayurveda came to earth and human beings started utilizing this science for living disease free in a natural way.
For a long time the teaching of Ayurveda was oral from teacher to disciple but Agnivesh, a disciple of Punarvasu Atreya, the master of Ayurveda put the Ayurveda knowledge in writing and named the text as Agnivesh Tantra which was redacted by Charak. This work by Charak is today known as Charak Samhita and is the most famous book on Ayurveda medicine. Similar texts were prepared by other disciples of Punarvasu Atreya but they are not used often in these days. In the field of surgery Susrut samhita is quite famous which is authored by Susruta, a disciple of Lord Dhanwantri. Based on the timing of these texts some scholars believe Ayurveda to be about 5000 year old science.
The main emphasis in the Ayurveda was on herbal medicine but in 8th century onwards Nagarjuna, the great alchemist introduced mercury and other minerals to Ayurveda medicine and these metals and minerals were adopted very soon because of their fast action and small dosage. These metals and minerals being used in Ayurveda were first subjected to specific processes called Shodhan (Purification) and Maran (Process to help the metal assimilate in the body). This was the golden period of Ayurveda, as Kings at that time were keen for the better health of their people and they helped in propagation of Ayurveda by opening hospitals etc.
After this many scholars added new literature but all this was based on the old texts only. The most important of these is Ashtang hridya and Ashtang samgraha by Vagbhatta. There were texts on herbs like Bhav prakash nighantu, a collection of herbs and metals etc. used in Ayurveda.
Ayurveda was at its peak when mughals invaded India and with this started the downfall of Ayurveda due to Apathy of the rulers of India. Even during adverse circumstances teaching and learning of Ayurveda continued, though at a low level. Hakims and Vaidyas were working together and many things has been exchanged between Unani medicine and Ayurveda. During the British rule some Ayurveda colleges were established along with medical colleges initially but later on they were almost closed and teaching of Ayurveda once again continued at low level.
In India Ayurveda was being taught in a non uniform way that means every state had a different syllabus and pattern of study and it continued for a long time even after establishment of a separate university of Ayurveda at Jamnagar in Gujrat. In the year 1970 central council of Indian medicine was formed by passing an act in parliament thus paving the way for a uniform syllabus and pattern. It is still the regulating body for teaching of Ayurveda in India.
In late 1970s western countries started taking interest in Ayurveda and many teachers of Ayurveda migrated to Europe and many scholars came to India.Today there are many organizations in the world which are engaged in teaching and propagation of Ayurveda. Presently Indian government is also trying to associate latest medical research with the traditional knowledge of Ayurveda.
Susrut samhita is an old text of Ayurveda and it is a text mainly dealing with surgery in Ayurveda. It is written by Susruta, so it is called susruta samhita. Samhita means a text containing knowledge on a subject in datail.
Ashtang samgrah is also another text written by Vagbhatta who was an ayurveda scholar in approx. 8th centuary AD. This text is called Ashtang because it contains details of all the EIGHT (Ashta means eight in sanskrit)divisons of Ayurveda. the word samgrah denotes that it is a mere complation of subject matter scattered here n there in various old texts of Ayurveda like Susruta on surgery, charak samhita on medicine, Kashyap samhita on paediatrics etc. So Ahtang samgraha is the text of Ayurveda having a collection of relevant things on all the 8 divisons of Ayurveda. But along with compiling the things Vagbhatta has also given some new things in his text.
Ashtang hridya is a short version of Ashtang samgraha, we can think of Ashtang samgraha as the text book of Ayurveda and ashtang hridya as its handbook. It is called Ashtang hridya because hridya is the most important organ of the body similarly this text contains the most important parts of the Text Ashtang Samgraha.
This is again a text on herbology basically. This is a text written by BHAV MISHRA a author of 16th centuary. The texts dealing with the drugs-herbal, mineral or of animal origin are called Nighantu. So this is a text by BHav Mishra and it contains details of the plants, minerals,and other drug material used in ayurveda.