### Clue: Respiratory problem a normal one — all going back to drink (12)
### Answer: SARSAPARILLA 
 ### Explanation: Definition: drink
 SARS(abbrev. for "severe acute respiratory syndrome", a deadly viral pneumonia) + A + PAR(equal to the norm, as in "par for the course") + I(Roman numeral for "one") + **reversal of**(going back) ALL.
Answer: A non-alcoholic drink made from the roots of the plant of the same name.