Doctor a bad skin with certain fluids (6)
I believe the answer is:
drinks
'fluids' is the definition.
(drink is a kind of fluid)
'doctor a bad skin with certain' is the wordplay.
I cannot really see how this works, but
'doctor' could be 'dr' (abbreviation) and 'dr' is found within the answer.
an anagram of 'skin' is 'inks' which is within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for drinks that I've seen before include "Consumes alcohol" , "Beverages" , "they are to be swallowed" , "Quaffs, imbibes" , "Swallows liquids" .)