Magic drug, not a thing helping save Romeo (4,6)
I believe the answer is:
love potion
'save romeo' is the definition.
The definition suggests a singular noun which matches the answer.
'magic drug not a thing helping' is the wordplay.
I cannot really understand how this works, but
'drug' could be 'pot' (slang term for cannabis) and 'pot' is located in the answer.
'not' could be 'o' (I've seen this in other clues) and 'o' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for love potion that I've seen before include "Magic drink stimulating desire" , "preparation for it" , "Aphrodisiac needed!" .)