Eucalyptus could reduce your allergic symptoms Hay fever often leads to a build-up in congestion which can make it difficult to breathe. Eucalyptus Oil is known as the ‘breathing oil’ due to its anti-inflammatory properties that can ease congestion and improve your breathing pattern. Research is ongoing to determine further benefits it may be able to offer in addition to reducing allergic symptoms. You could try diffusing eucalyptus essential oil into the air, so you breathe it in naturally, or try inhaling it directly from the bottle.