Source Naturals Wellness Oil of Oregano.5oz (14.78 mL) Source Naturals Wellness Oil of Oregano is made from wildcrafted true oregano (Origanum vulgare), an aromatic herb that is native to the Mediterranean region. Traditionally, oregano was used to support digestive, respiratory and joint health. Recent in vitro research indicates that carvacrol, an active constituent of oil of oregano, may provide support to the immune system. Source Naturals Wellness Oil of Oregano is the most potent on the market and is standardized to 70% carvacrol. Source Naturals Wellness Oil of Oregano Antioxidant DefenseWhile carr ying out their immune functions, white blood cells generate free radicals, highly reactive molecules that can damage the very white blood cells that produce them. Vitamin C, a free radical scavenger, is concentrated in certain white blood cells, providing them with a built-in defense mechanism. Bioflavonoids act as cofactors that complement the action of vitamin C.