Medicinal compound men start taking on holiday? (7)
I believe the answer is:
menthol
'medicinal compound' is the definition.
(I've seen this before)
'men start taking on holiday?' is the wordplay.
'start' suggests taking the first letters.
'on' says to put letters next to each other.
'holiday?' becomes 'hol' (short for holiday).
The initial letter of 'taking' is 't'.
'men'+'t'+'hol'='MENTHOL'
(Other definitions for menthol that I've seen before include "Peppermint oil derivative" , "Chemical compound that smells like mint" , "Minty substance" , "mild analgesic" , "medicinal compound" .)