Natural Factors - Organic Oil of Oregano - 1 fl. oz. (30 mg.) Natural Factors Organic Oil of Oregano is an antioxidant for the maintenance of good health. It has been traditionally used by herbalists to support immune health. Natural Factors Organic Oil of Oregano includes minimum 80% carvacrol the primary indicator of an oregano oil?s strength. It is blended in a 1:1 ratio with organic cold-pressed extra-virgin olive oil for improved absorption and consistency.