Epsom salts vs plural

Epsom salts and plural both are nouns.

Word	Noun	Adjective	Verb	Adverb
Epsom salts	Yes	No	No	No
plural	Yes	Yes	No	No

Epsom salts (noun)	plural (noun)
(used with a singular noun) hydrated magnesium sulfate used as a laxative	the form of a word that is used to denote more than one
hydrated magnesium sulfate that is taken orally to treat heartburn and constipation and injected to prevent seizures

Epsom salts (adjective)	plural (adjective)
	grammatical number category referring to two or more items or units
	composed of more than one member, set, or kind