Oregano Oil: The essential oil of oregano derived from the leaves and flowers of the Oreganum vulgare a member of the perennial herb and mint family. The oil of oregano is very powerful with a spicy aroma and intense taste that may be strong enough to numb the tongue for a few seconds. Take this at the first sign of feeling sick or under the weather. Place 1-3 drops directly under tongue and hold for 30 seconds prior to swallowing. Rinse mouth by drinking water.