In this study, we investigated the therapeutic efficacy of the plant compounds trans-cinnamaldehyde (TC) and eugenol (EG) on reducing Salmonella enterica serovar Enteritidis (SE) in commercial, market-age broiler chickens. Straight run, day-old commercial broiler chicks (N = 84) were randomly grouped into 6 groups of 14 birds each (n = 14/group): a negative control (no SE, no TC or EG), EG control (no SE, 1% EG), TC control (no SE, 0.75% TC), a positive control (SE, no TC or EG), an EG challenge group (SE, 1% EG), and a TC challenge group (SE, 0.75% TC). Before the start of each experiment, the flock was screened for any inherent Salmonella (n = 12 birds/experiment). Birds were given ad libitum access to Salmonella-free feed and water. On d 30, birds were challenged with a 4-strain mixture of SE (8 log10 cfu/bird). Two birds from each group were killed after 24 h (d 31) to check for colonization of SE in the cecum. Birds were given feed supplemented with TC (0.75%) or EG (1%) for 5 d before slaughter on d 42 (n = 10 birds/group) for determination of SE populations in the cecum and cloaca. The experiment was repeated 2 times. The trans-cinnamaldehyde and EG consistently reduced SE in the samples in both experiments (P < 0.05). Body weights and feed consumption did not differ among the groups (P > 0.05). On the basis of histological analysis, no abnormal changes in the liver were observed because of supplementation of plant compounds. Therefore, TC and EG supplemented through the feed could reduce SE colonization in market-age chickens.