This study evaluated the functional effects of two chemotypes of oregano essential oil (OEO): Lippia Origanoides (LO) and a comercial product Synergy Essence (SE). Broilers were randomly assigned to one of eight dietary treatments: 1) Basal diet (BD); 2) BD+ antibiotic growth promoters (AGP)(bacitracin 50g/ton); 3) BD+ LO125 (125g/ton); 4) BD+ LO250 (250g/ton); 5) BD+ LO500 (500g/ton); 6) BD+ SE125 (125g/ton); 7) BD+ SE250 (250g/ton); 8) BD+ SE500 (500g/ton). At the time of slaughter (42 d), five birds per treatment were