alterative vs curative

alterative is not a noun while curative is a noun.

Word	Noun	Adjective	Verb	Adverb
alterative	No	Yes	No	No
curative	Yes	Yes	No	No

As adjectives, alterative and curative are synonyms defined as:

Other synonyms of alterative include healing, remedial, sanative, therapeutic.

alterative (noun)	curative (noun)
	a medicine or therapy that cures disease or relieve pain

alterative (adjective)	curative (adjective)
tending to cure or restore to health	tending to cure or restore to health