The invention relates to a method of adding flavor to a chewing gum core of a chewing gum, said chewing gum comprising active pharmaceutical ingredients, said method of adding flavor to a chewing gum core comprising the steps of: - providing a chewing gum core comprising gum base - impregnating said chewing gum core by adding at least one dose of liquid flavor mixture onto the chewing gum core prior to any optional coating of the chewing gum core, wherein at least the flavor in the liquid flavor mixture has affinity for the gum base in the chewing gum core.