It comes after a 24-year-old driver was found to be over the legal drink-drive limit during a routine control in Munich.
He was taken to the police station where blood tests found he had no alcohol in his system.
The man was released after officers found the strongest thing he had taken was a Fisherman's Friend.
Forensic doctor Thomas Gilg said the essential oils contained in the throat sweets reacted in the same way as alcohol on hand-held breathalysers.
He said in tests they found just three of the mentholated sweets could cause a motorist to test three times over the legal limit.