Oregano includes several genera and species, the most common being European Origanum vulgare, and Mexican Lippia graveolens. The chemical composition of essential oils and aqueous extracts from Mexican oregano (Lippia graveolens Kunth), air-dried with or without exposure to sunlight, was determined. The main essential oil components were thymol (66%) and carvacrol (1.9%) and their precursors, p-cymene (10%) and y-terpinene (2.8%). Total polyphenol content of the aqueous extract of L. graveolens was 656 μg eq. EGCG/g dry leaves. Volatile composition was affected by sun-drying which lead to the formation of oxidized derivatives. Mexican oregano is a rich source of flavor and phenolic compounds.