The essential oils from the leaves of Lippia oreganoides collected in June 2003 (rainy season) and February 2004 (dry season) were analyzed by GC/MS. Thymol (61.9% and 44.7%, respectively) and carvacrol (7.9% and 16.8%, respectively) proved to be the major constituents of both collections. Linalool (0.4%) was present only in the collection made in June 2003, while carvacryl acetate (0.6% and caryophyllene oxide (1.6%) were only detected in the February 2004 collection.
