Complaint when her pint is spilt (9)
I believe the answer is:
nephritis
'complaint' is the definition.
(nephritis is a kind of health problem)
'her pint is spilt' is the wordplay.
'spilt' indicates anagramming the letters.
'her'+'pint'+'is'='herpintis'
'herpintis' anagrammed gives 'NEPHRITIS'.
'when' is the link.
(Other definitions for nephritis that I've seen before include "kidney complaint" , "Inflammation of the kidneys" .)