Antioxidant supplementation, especially with the plant Scutellaria baicalensis (SB), could limit the oxidative stress that is prone to appear at the beginning of lactation in the mammary tissue of dairy cows. Recent studies showed that SB extract could increase milk production and increase the survival of mammary epithelial cells (MEC) in bovine. These effects could be linked to a change in the antioxidant response of MEC. To study this potential effect, cows received a diet supplemented (n=8) or not (n=11) with 1 g/d of SB from calving until 150 d of lactation. Milk samples were collected at d30, d50, d130 and d150 after calving to purify the MEC from the milk by an immunomagnetic method in order to study by RT-PCR the mRNA level of genes involved in milk synthesis, cell death and the antioxidant response. Data were analysed using an ANOVA taking into account time (day), SB treatment and the interaction of both as fixed effects, and cow as a random effect. SB did not globally significantly affect the expression of genes involved in milk synthesis (LALBA, CNS3, and SLC2A1) or in cell death (BAX, BCL2). However, at d150, CSN3 mRNA level tended to be more expressed in milk purified MEC in SB treated cows than in control cows (P=0.07). SB treatment increased SOD1 mRNA levels compared with control treatment (+66%, P=0.05). SB did not affect the other genes involved in the antioxidant response (SOD2, TRxR1, GPX1, GPX3, CAT) excepted for a significant increase in GPX1 (+51%, P=0.03) at a specific time of milk sampling (d130). The gene expression of nuclear factor erythroid 2-related factor 2 (Nrf2) had a tendency to increase at d150 (P=0.06). This effect could trigger the previously observed reduced cell death in the milk purified MEC and the increase in GPX1 and SOD1 transcripts. In conclusion, SB induced positive effects on the expression of genes involved in the antioxidant response in milk purified MEC.