Remedy, counteragent (8)
I believe the answer is:
antidote
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">remedy</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that antidote is a type of remedy)</span><br/ ><br/ >'<span class="explanation-format__original">counteragent</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ ></span>
(Other definitions for antidote that I've seen before include "It makes you feel better" , "Donate it to anti-poison agent" , "Tied to an awful counteracting agent" , "Counterpoison" , "Counteractive medicine" .)