Two ingredients can trigger allergies in Denttabs Mint toothpaste tabs:Menthol: The substance provides fresh breath and leaves a pleasant cool feeling. He travels thereby through your mucous membranes and could cause allergic reactions.  Eugenol: Eugenol is part of our mint flavor and a potent allergen. We will launch toothpaste tabs without menthol and flavoring for allergy sufferers in the future.