The term literally means that which supports the body functions. They form the basic functional tissues of the body and are seven in number:
The Dhatus are formed as a result of the digestion process and are composed of the Panchamahabhuthas (Air, water, fire, space and earth) with dominancy of one or more elements in each:
When the food is broken down by the digestive fire, two components are formed namely, saar (the nourishing element) and mala (waste products). The saar nourishes the various Dhatus thus sustaining and maintaining the health of the body. The ingested food is converted into the Dhatus thus:
Food - Rasa/Plasma - Raktha/Blood - Mamsa/Muscle - Medas/Fat - Asthi/Bone - Majja/Bone Marrow - Sukra/Semen and Ovum
Like the Doshas, Dhatus can also become vitiated and cause diseases.
Upadhatus are those components which support the body functions but do not take part in the regeneration of other Dhatus. Produced by the Dhatus, Upadhatus are seven in number: