Malas: Malas or waste materias are constituents eliminated from body during the normal course of metabolism. The three main malas are urine (mutra), faeces (purisha) and sweat (sweda).

Also subtle waste materials (kleda) are eliminated from epithelial linings of the eyes, nose, mouth, ears and genital organs. Main tissue that related to kapha is plasma which produces kapha (mucus) as waste material. Main tissue that relates to pitta is blood which produces pitta (bile or excess blood) as a waste material. Main tissue that relates to vata is bone which holds vata in its joints and porous spaces.

In Ayurveda, the malas are such excretory products of the body which continue to play vital physiological role in the system.  

(Dosha-dhatu-malamulam hi sararam). 

Malas are considered as sustainer of life in the same way as the dhatus when they exist in appropriate limits.

The extreme loss of the malas or excess of malas in body leads to disease .That is why Ayurveda focus on proper functioning of malas in body (samadhatu-malakriyah).