He was 68.
Dr Namboothiri is survived by his wife and four children.
He was undergoing treatment at the hospital for some illness, they said
Dr Namboothiri, Managing Director of Sreedhareeyam Ayurvedic Hospital and Research Centre at nearby Koothattukulam, is known for his contribution in transforming the science of "Ayurveda Ophthalmology" to offer solutions where modern medicine has no effective answers in the field.
He started Sreedhareeyam Ayurveda Eye Hospital and Research Centre in his ancestral house in 1999.
Dr Namboothiri developed and popularized classical ayurvedic formulations and treatment procedures of Ayurveda (NetraKriyaKalpas) - so far confined only to classical Ayurvedic textbooks, they said.
He specifically chose to specialize on all ailments related to ophthalmology, diagnosed root-causes, delved into the anatomy and independently chiseled a curative system.