Rasa refers to liquids and rasa dhatu is comprised of all the fluids in the body:  plasma, interstitial and synovial fluids, and secretions, including breast milk.  Balance is maintained by consuming water, juices from fruits and vegetables, coconut water, herbal teas, and salts that have trace minerals.  Some herbs also help to build quality fluids and/or detoxify the plasma and lymphatic system.

Ayurvedic medicine distinguishes between the plasma and the blood cells circulating in the plasma.  Rasa is the liquid and it carries nutrients that will be utilized by the blood cells at the second stage of regeneration. 

One of the best herbs for purifying the plasma is haritaki.  Guduchi also supports all stages of regeneration.