Group of hospital patients tucking into dessert later (10)
I believe the answer is:
afterwards
'later' is the definition.
(synonyms)
'group of hospital patients tucking into dessert' is the wordplay.
'group of hospital patients' becomes 'ward' (patients on a hospital ward).
'tucking into' indicates putting letters inside.
'dessert' becomes 'afters' (afters can mean a dessert course).
'ward' placed into 'afters' is 'AFTERWARDS'.
(Other definitions for afterwards that I've seen before include "Subsequently" , "Later on" .)