<p>In a technified production system, the feeding is mainly based on the use of commercial balanced foods, which allow getting good productive performances in terms of daily gain of weight, conversion and feeding efficiency; however, the use of them generates a high cost in the production, for this reason, the inclusion of supplements or additives in the animal diets has been sought. In the beginning, antibiotics were used as growth promoters (AGP) however, as time went by, it became necessary to look for alternatives to the use of AGPs because of the concern about the effect on the emergence of resistant strains of bacteria that could affect human health. As a result, the research processes with the use of aromatic plants arose, among which oregano (Origanum vulgare) has stood out for the effect of its essential oils (thymol and carvacol) on the productive parameters in different animal exploitations, mainly pigs and birds.</p>