Ayurveda even though present all over India, due to Kerala’s geographical and historical advantages has been able to keep its purity and sanctity.
India, especially Northern India were under external aggressions and rule for several centuries. But Kerala has never been under the rule of such external forces, who were always promoting Unani instead of Ayurveda.
Kerala was well protected by western ghats on one side and by sea on the other.
The lush green flora and fauna nursed by abundant rains helped in availability of even rare herbs. The weather and the climate that never goes to extreme is helpful in treatment.
So here developed Special Ayurveda treatments like Pizhichil, Njavara Kizhi, Shirovathy, Thalapothichil etc. And more over Kerala is traditionally the home land of Ashta Vaidya.