Warnings - Cinnamon bark oil is best avoided during pregancy and while breastfeeding. Cinnamon bark oil is best avoided by babies and young children. If used in excess, Nutmeg essential oil can cause toxic symptoms. Nutmeg oil is best avoided during pregancy and while breastfeeding. Nutmeg oil is best avoided by babies and young children. Clove oil is best avoided during pregancy. Clove oil is best avoided by babies and young children.