Drug addicts in Pittsburgh in the United States have been getting their fix from an unusual source: McDonald's Happy Meals.

A woman has been arrested after giving some customers a little extra in their boxes.

People at the drive-in who knew to ask for a "Happy Meal boy’s toy" would pay extra and get heroin as well. Shantia Dennis has been arrested on suspicion of dealing drugs.

Police Chief Greg Geppert said: "They would go up to the window, the girl would charge them $2 for that toy and $80 which they would give her for the heroin that would come in the box."

Authorities are investigating whether the alleged scheme has any links to another man,Theodore Upshaw, who was arrested in nearby Murrysville, also for selling heroin from a McDonald's.