Dozens and dozens work around hospital department (6)
I believe the answer is:
plenty
'dozens and dozens' is the definition.
'work around hospital department' is the wordplay.
'work' becomes 'ply' (to ply a trade is to work at it).
'around' indicates putting letters inside.
'hospital department' becomes 'ENT' (abbreviation for Ear, Nose and Throat department).
'ply' enclosing 'ent' is 'PLENTY'.
(Other definitions for plenty that I've seen before include "Ample quantity" , "A great deal" , "Copiousness" , "Amplitude or abundance" , "As much as necessary" .)