» The use of Rasayanas for immunity and Ojas

Rasayana is an Ayurvedic rejuvenation therapy which helps in maintenance & promotion of health . Rasayana essentially means nutrition at all levels from macro to micro-cellular level. Rasayana therapy replenishes the vital fluids of the body; boost the Ojas (vital force of life). Ojas, when well formed, helps keep away diseases and prevents ill effects of advanced age. 

Rasayana  brings about the normalcy of Rasa dhatu (first of the seven tissues) and thereby maintains other dhatus (body tissues) in equilibrium for a longer period. Such a state of improved nutrition prevents ageing which can be understood as Vayasthapana or Jaranasana (geriatric care).

It is a science of rejuvenation of cells and tissues in the body system.

The Rasayana drugs are mainly classified as Kamya Rasayana (for promotion of health of individuals) and Naimittika Rasayana (for cure of diseases). Kamya Rasayana can be further classified in intellect promoting, glow-complexion promoting or increasing the Prana (life force or vitality). 

The Rasayanas are therefore used to enhance physical strength and improve the overall health. Rasayanas are mostly in polyherbal compositions and are prepared with herbs and minerals.