You can start to use Vicks First Defence from the 1st symptoms or during the first steps of a cold, before it grows worse.<br /><br />Vicks First Defence Nasal Spray works into the deep nasal cavity, where the viruses of colds and fly set up and grow.<br /><br />Vicks First Defence is a micro-nasal gel, formulated with a base derived from plant extracts, which encapsulates the virus responsible for colds and helps our body to eliminate it.