What may reduce inflammation in fowl on frozen water (8)
I believe the answer is:
poultice
'what may reduce inflammation' is the definition.
(a poultice might relieve inflammation)
'fowl on frozen water' is the wordplay.
'fowl' becomes 'poult' (poult can mean a young poultry bird).
'on' says to put letters next to each other.
'frozen water' becomes 'ice' (I've seen this in another clue).
'poult'+'ice'='POULTICE'
'in' is the link.
(Other definitions for poultice that I've seen before include "It relieves inflammation" , "one's meant to soothe" , "Moist, hot, skin application" , "Heated medical application for drawing pus" , "Soft material wrapped in cloth to relieve inflammation" .)