The noun antidote means a chemical, especially a drug that limits the effects of a poison.

Synonyms are corrective, countermeasure, cure, or remedy.

The word origins from Old French (early 15th century) antidot meaning “remedy counteracting poison”, and directly from Latin antidotum/antidotus meaning “a remedy against poison”. It also comes from Greek antidoton meaning “given as a remedy”, literally meaning “give against”. It is derived from anti meaning “against” plus didonai meaning “to give”.

We need to buy an antidote for snake venom.

She believed that exercise is an antidote for depression.

This antidote delays the toxic effect of the poison.