Endless mineral water to drink following illness and unpleasant discharge (8)
I believe the answer is:
effluvia
'endless mineral water to drink' is the definition.
I can't judge whether this definition defines the answer.
'illness and unpleasant discharge' is the wordplay.
I cannot really understand how this works, but
'illness' could be 'flu' (flu is a kind of illness) and 'flu' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
'following' is the link.
Can you help me to learn more?
(Other definitions for effluvia that I've seen before include "Unpleasant discharges" , "disagreeable vapours" , "nasty exhalations" , "Nasty smells" , "nasty vapours" .)