Early and abrupt weaning is a critical period for piglets with a high prevalence of digestive disorders. Plant-derived products are potential alternatives to antibiotics to prevent and treat post-weaning diarrhoea through their antioxidant, anti-inflammatory or anti-bacterial properties. The study aimed to investigate the effects of plant-derived product supplementation on sow and piglet physiology during lactation and around weaning. Sixty-four sows were assigned to control or extract treatment. Extract sows were supplemented with 25 g/d of plant extract supplied in feed from day of gestation (DG) 106 to day of lactation (DL) 28 and received 20 ml of a mixture of essential oils on DG109. Within each sow group, 2 ml of a mixture of essential oils (EO) was orally administrated to all the piglets of 1 litter out of 2 at DL3. Piglets were weaned on DL28. Blood samples were collected from sows on DG94, DG112 and DL26 and from 2 piglets per litter on DL25 and 5 d post-weaning (PW5) for the analyses of blood cell count, plasma metabolites and inflammatory (haptoglobin) and oxidative (oxidative products, dROM, and antioxidant capacity, BAP) status indicators. Colostrum and milk samples were collected at farrowing and at DL6 and 26. Extract treatment had no effect on sow metabolic, inflammatory and oxidative status or nutritional composition of colostrum and milk at DL6 (P>0.10). However, it decreased the number of lymphocytes in sow blood at DG112 (P<0.05). It also tended to decrease dry matter and gross energy (P<0.10) and reduced haptoglobin concentration (P<0.01) in milk at DL26. The EO treatment increased the average daily gain of piglets from DL6 to weaning (P<0.05), regardless of sow treatment. In piglet blood at DL25, EO tended to increase the lymphocytes proportion (P<0.10), decreased the granulocytes proportion (P<0.05) and tended to decrease the oxidative stress index (OSI=dROM/BAP, P=0.06). Piglet OSI and blood concentrations of haptoglobin and leukocytes were increased by weaning but not affected by sow or piglet treatments. Plant-derived products could thus modify the mammary secretions composition and health status of piglets before weaning. This study was financially supported by the Pays de la Loire region.