Oil of Oregano Liquid 1 fl oz, Planetary HerbalsOil of Oregano Liquid Herbal Supplement Immune System Support Planetary Formulas Oil of Oregano is sourced 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. Supplement Facts