The effects of two doses of a verbascoside-based dietary supplement on performance, some blood parameters, and plasma oxidative status in Lacaune suckling lambs were investigated. Twenty-four lambs were divided into three groups of eight animals each and fed per os a dietary supplement with a plant extract from Lippia citriodora containing a phenylpropanoid glycoside, verbascoside: the low-verbascoside (LVB) group received 2.5 mg per animal per day of natural extract, the high-verbascoside (HVB) group received 5.0 mg per animal per day, the control group (CON) did not receive dietary supplementation. The body weight, average daily gain, milk consumption and milk conversion index were determined for the experimental and control animals and blood samples were taken from all lambs. Dietary supplementation with verbascoside in both the LVB and HVB groups resulted in improved average daily gain (P < 0.01), milk consumption (p < 0.05), and serum lipid profile; the groups showed a decrease in triglycerides (p < 0.05) and an increase in high density lipoprotein cholesterol levels (p < 0.05). Plasma oxidative status in lambs supplemented with verbascoside showed an improvement in homoeostatic stability that induced a significant decrease in reactive oxygen metabolites (P < 0.01) and thiobarbituric acid-reactive substances (p < 0.05) concentrations and a marked increase in serum concentrations of vitamin E (P < 0.01) and vitamin A (p < 0.05).