Dose may upset Siberian dog (7)
I believe the answer is:
samoyed
'siberian dog' is the definition.
(I've seen this before)
'dose may upset' is the wordplay.
'upset' indicates anagramming the letters.
'dose'+'may'='dosemay'
'dosemay' is an anagram of 'SAMOYED'.
(Other definitions for samoyed that I've seen before include "one barking" , "Sled dog" , "Breed of white dog from Siberia - May's ode (anag)" , "Some day (anag) - dog (from Siberia?)" , "Siberian dog" .)