Breathing in the gas is not illegal but can pose serious health risks. The 20-year-old has apologised for failing to set "the right example" but has been involved in controversy already this season, having been involved in a dressing-room row with team-mate James Morrison. The Scot is understood to have hit Berahino during the bust up.
"[Inhaling nitrous oxide] was very poor judgment on my part," he said. "I won't be doing it again."