The study determined the effects of Lactobacillus fermentum I5007 administered early in the life of piglets on their growth, faecal microflora, immune index and antioxidant activity. Twelve litters of 3-day-old crossbreed piglets were randomly assigned to either of two treatments: piglets in the control group were orally administered 2 ml saline per day per piglet from day 3 to day 5 of life; piglets in the probiotics group were given 2 ml rejuvenation liquid of L. fermentum spray-dried powder (≥ 10⁹ CFU ml^–1). Compared with the control group, oral administration of L. fermentum tended to increase the weight gain (P < 0.10) of piglets from day 3 until day 17 of life, and significantly (P < 0.05) increased the number of Lactobacillus in faeces, the concentrations of IgM, IgG, IgA and glutathione, the activity of glutathione peroxidase, and the total antioxidant capacity in plasma of piglets on day 17. In conclusion, oral administration of L. fermentum to piglets early in life could be beneficial by establishing appropriate intestinal microbial flora.