This German concoction may give you bad dreams (10)
I believe the answer is:
nightmares
'bad dreams' is the definition.
(I've seen this before)
'this german concoction' is the wordplay.
'concoction' indicates an anagram.
'this'+'german'='thisgerman'
'thisgerman' anagrammed gives 'NIGHTMARES'.
'may give you' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for nightmares that I've seen before include "Bad dreams" , "Dreads" , "trials" .)