Dravyabhedah - types of substances

There are no universal eating rules in Ayurveda. The qualities of individual ingredients as well as of the body are desribed with the same terminology, by means of Gunas and Doshas. Ayurveda also says that health consists of balance. When a Dosha is increased in the body, Ayurveda recommends using ingredients with opposite qualities in order to reach balance and health. Increasing Doshas is called Kopana, alleviating/reducing Doshas is called Shamana and keeping Doshas balanced is called Swasthahita.

For example, a person with increased Pitta has various bleedings, inflammations, blood thinnig, diarrhoea, long menstruation, becomes tired easily and is hypermobile at the same time, etc. When such a person uses ginger, garlic, spirit etc., he will become Kopana, i,e., the Dosha will increase and the problem will not be solved. On the contrary, Pitta will be even more aggravated. If he uses pomegranate, mint, ghee, Brahmi, nagar motha, etc., instead, then the increased Pitta would be alleviated (Shamana).

When a person has balanced Doshas and wants to keep them this way, he will ingest balanced food. To use food and ingredients in order to promote health and nourishment in this way is called Swasthahita, as is anything that promotes life.

Every dravya has five aspects of its dharma:  ras (flavor), prabhav (impression, effect), where the prabhav can be of three kinds - shamana, kopana and swasthahita. 

These are also the tatthvi.

The substance, the essence, is not material, it is immaterial.