Nouns

(n)adjuvantan additive that enhances the effectiveness of medical treatment

Adjectives

(s)accessory, adjunct, ancillary, adjuvant, appurtenant, auxiliaryfurnishing added support“an ancillary pump”, “an adjuvant discipline to forms of mysticism”, “The mind and emotions are auxiliary to each other”
(s)adjuvantenhancing the action of a medical treatment“the adjuvant action of certain bacteria”