Cannabis regularly taken eating chicken Madras! (7)
I believe the answer is:
chennai
'madras' is the definition.
(I've seen this before)
'cannabis regularly taken eating chicken' is the wordplay.
'regularly taken' means one should take alternating letters (letters taken at regular intervals).
'eating' indicates putting letters inside.
'chicken' becomes 'hen' (hen is a kind of chicken).
The alternating letters of 'cannabis' are 'cnai'.
'cnai' going around 'hen' is 'CHENNAI'.
(Other definitions for chennai that I've seen before include "Indian city, formerly called Madras" , "Indian port" , "Current name for Madras" , "Official name for Madras" , "City previously called Madras" .)