First Defence Micro-Gel Nasal Spray enhanced with plant extracts. Fights cold germs before they can take hold. First Defence nasal spray targets the area deep inside the nasal cavity where cold germs first take hold and multiply. It works by trapping cold causing germs and helping your body to remove them naturally. - Prepare and Use: Always read the label. Please read enclosed leaflet carefully for complete product information. When first using First Defence it is normal to experience increased nasal discharge and a temporary stinging or smarting sensation.