Invigorating medicine (5)
I believe the answer is:
tonic
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">invigorating medicine</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for tonic that I've seen before include "Small drink of spirits" , "something invigorating" , "Carbonated mixer" , "Stimulant" , "fizz" .)