The term Dhatu is used in Ayurveda in 2 different contexts. With reference to the Sharira (body), Dhatus refer to those vital body tissues that are responsible to hold and sustain life. These are the basic building blocks of the physical body and they are 7 in number. On the other side, with reference to the pharmacology, Materia medica and Iatrochemistry in Ayurveda, Dhatus indicate ‘Metals’ like gold, silver, copper.
Sharira Dhatu (Vital body tissues)
Dhatus pertaining to the Sharira (physical body) are called as Sharira Dhatu. They are also considered as the vital body tissues.
Ayurveda states that 7 dhatus constitute the physical body of an individual. They have specific function in maintenance of life and they also perform the important task of nourishing the entire structure of the body. It is believed that, living body can not afford to loss of any of these 7 dhatus to any extent and if it occurs leads to serious damage to the body.
Significance of Dhatus
Collectively they establish immune mechanism for the physical body. Their equilibrium is described as the state of health. Thus, the ultimate aim of any Chikitsa (treatment modality) in Ayurveda is to establish the equilibrium of all the dhatus. They provide the seat for Doshas and let them control the body. Strength of the Dhatus is the critical factor for one’s immunity and overall health.
7 Dhatus described in Ayurveda compendium are as follows,
- Rasa- essense of nutrition, roughly correlated with lymph or plasma
Traditional texts often refer to the above as the Seven Dhātus (Saptadhātus). Ojas is known as the eighth Dhātu or quintessence of these 7 dhatus.
Dhatu in Rasashastra (Metals in Ayurveda Iatro-chemistry)
The materia medica of Ayurveda includes various mineral and metallic substances as well. These metals and minerals are classified into vaarious categories on the basis of their common features and application in pharmacology. Generally these drugs are classified in to four distinct classes named- Rasas, Dhatus, Ratnas and Vishas. The class of ‘Rasa’ is predominantly possessing ‘Rasaayana’ (adaptogenic effect) effect. Dhatus are grouped together on account of their capacity to provide structural strength to the body. The minerals possessing gem quality are grouped as Ratna, whereas inherently highly poisonous plants are grouped as Visha. (Savrikar SS, Ravishankar B. Introduction to 'Rasashaastra' the Iatrochemistry of Ayurveda. Afr J Tradit Complement Altern Med. 2011;8(5 Suppl):66–82. doi:10.4314/ajtcam.v8i5S.1)
Use of Dhatus
(To be edited)The therapeutic properties of metals like the Gold, Silver, Copper, Iron, Lead and Tin and alloy Bronze (Bell metal) are described by Acharya Sushruta (Sushruta Samhitaa 1992b-Susruta Sutra 46/326-330). Although the mineral and metallic formulations are described in the classics belonging to ‘Samhitaa’ and ‘Post-samhitaa’ period, the processing technique of these materials in these periods differs considerably.
Following metals are considered under Dhatu category in Rasashastra. These metals are widely used in various classical Ayurveda formulation after rigorous processing and purification in order to make them bio-available to body tissues on oral consumption.
- Gold (Suvarna)
- Silver (Raupya)
- Copper (Taamra)
- Iron (Loha)
- Lead (Naaga)
- Tin (Vanga)