Part of the hospital care for the white powder (4)
I believe the answer is:
talc
'the white powder' is the definition.
(I've seen this before)
'part of the hospital care' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'TALC' can be found hidden inside 'the hospital care'.
'for' is the link.
(Other definitions for talc that I've seen before include "Magnesium silicate powder" , "It is used to absorb moisture" , "(Mineral providing) powder" , "Softest substance in Mohs scale of hardness" , "Softest mineral on Mohs hardness scale" .)