Antimicrobial In piglets, carvacrol, thymol, eugenol, and cinnamaldehyde were found to be absorbed nearly completely in the stomach and the proximal small intestine within 2 h after oral administration (Michiels et al., 2008). Therefore, to deliver the essential oils and their antimicrobial activities to the hindgut to favorably modify the microflora ecosystem, essential oils need to be protected to circumvent the absorption in the foregut (de Lange et al., 2010).