Health organisation (12)
I believe the answer is:
constitution
I believe this clue is a double definition.
'health' is the first definition.
(thesaurus)
'organisation' is the second definition.
('constitution' can be a synonym of 'organization')
(Other definitions for constitution that I've seen before include "Body of principles governing a state" , "State of health; composition" , "make-up" , "(Person's) general state of health" , "legal system" .)