Remedy offered by minister, one very small to be swallowed (8)
I believe the answer is:
curative
'remedy' is the definition.
(synonyms)
'minister one very small to be swallowed' is the wordplay.
'minister' becomes 'curate' (synonyms).
'one' becomes 'I' (Roman numeral).
'very small' becomes 'v' (abbreviated or small form of 'very').
'to be swallowed' means one lot of letters goes inside another.
'i'+'v'='iv'
'curate' placed around 'iv' is 'CURATIVE'.
'offered by' is the link.
(Other definitions for curative that I've seen before include "Medicine" , "Restoring to health" , "health-giving" , "Therapeutic" , "Healing" .)