Mala?s are excretory elements. These are three and termed as Thrimalas-

(1) Pureesha (The Faeces)
(2) Mutra (The Urine)
(3) Sweda (The Sweat)

The word Thrimala is used, to refer 3 types of excretory systems present in the body and not just the excreta. Mala can be translated as metabolic end products. This means that each cell which is a living factory will produce, under the influence of the Doshas , wastes (mala) which in turn influence adversely the functions of the Dhatus that produce them.

Thus Dosha, Dhatu and Mala form a tripod of health