Rakta Dhatu — The Blood Tissue
Rakta (blood) is the second body tissue, the vehicle of life force, responsible for oxygenation, immunity, and the red vitality that characterizes physical health.
Rakta Dhatu corresponds primarily to the red blood cells and the functional components of blood. In Ayurveda, Rakta is the vehicle of Prana (vital force) and is responsible for the fundamental life-sustaining functions of oxygenation, immunity, and the maintenance of body temperature. Rakta's seat is the liver and spleen, which produce, store, and regulate it — a correspondence with modern hematology that is striking given the empirical methods available to ancient physicians. The quality of Rakta determines complexion, vitality, strength of the sense organs, and immunity to disease. Imbalanced Pitta in particular disturbs Rakta, producing inflammatory conditions, skin disorders, and bleeding disorders. The Rakta-Pitta connection anticipated modern medicine's understanding of the inflammatory cascade and the role of blood in systemic inflammation.
Rakta is the root of life. It sustains all activities of the living being.
Modern hematology confirms that blood serves precisely the life-sustaining functions Charaka described — oxygen transport, immune defense, clotting, and hormonal signaling — and the liver-spleen connection to blood health has been validated in the study of hemolytic anemias and portal hypertension.
Charaka Samhita