Pollenase allergy relief spray he nasal spray will not relieve the symptoms of nasal allergies immediately and can take two to three days to have its full effect it is therefore most effective to start using the nasal spray two to three days before you expect to get symptoms for example before the start of the pollen season or if you know you are going to be in contact with pets that give you the allergy for maximum benefit the spray should then be used regularly to keep the nasal inflamm