Allspice Oil is a wonderful oil to use in the diffuser during the fall and winter. If used at full-strength, it can be a potent mucous membrane irritant, so it's best blended at a low ratio with other essential oils before diffusing. I particularly like Allspice Oil blended with Orange Oil or Bergamot Oil. Allspice Essential Oil's high Eugenol (a phenol) content suggests that Allspice may act as an anti-viral oil.