Technical Abstract: This study investigated the therapeutic efficacy of food-grade plant compounds, trans-cinnamaldehyde (TC) and eugenol (EG) on reducing SE in commercial, market-age broiler chickens. In two separate experiments, day-old commercial broiler chicks were randomly grouped into six groups of 14 birds each (n=14/group): a negative control (no SE, no TC or EG), TC control (no SE, 0.75% TC), EG control (no SE, 1% EG), a positive control (SE, no TC or EG), a TC challenge group (SE, 0.75% TC) and an EG challenge group (SE, 1% EG). Before the start of each experiment, the flock was screened for any inherent Salmonella (n=2 birds/group). Birds were given ad-libitum access to Salmonella-free feed and water. On day 30, birds were challenged with a four-strain mix of SE. Two birds (n=2 birds/group) from each group were sacrificed after 24 h to ensure colonization with SE. Birds were given feed supplemented with TC (0.75%) or EG (1%) for 5 days before slaughter on day 42 (n=10 birds/group) for determination of SE populations in cecum and cloaca. TC and EG consistently reduced SE in the samples in both experiments. Body weights and feed consumption did not differ among the groups. Histological analysis revealed no pathological changes in the cecum or liver samples due to supplementation of plant molecules. The results suggest that TC and EG supplemented through feed could reduce SE colonization in market-age chickens.