In this article we study the effect of diets supplemented with two strains of Lactobacillus delbruckii subsp. bulgaricus (B3 and A13, which produced the highest and lowest amount of exopolysaccharide, respectively) on generation of intestinal nitric oxide (NO) and antioxidant status. The oxidative status in terms of thiobarbituric acid-reactive substances (TBARS) and NO levels in small intestinal tissues were measured. We also determined intestinal nonenzymatic antioxidant levels after supplementation with two strains of L. delbruckii subsp. bulgaricus. In rats, dietary supplementation with both lactobacilli strains resulted in a nearly 1.5-fold increase in NO level in the small intestine. Increases in NO production may contribute to lipid peroxidation in the small intestine. However, at the same time, diets supplemented with both strains of L. delbruckii subsp. bulgaricus enhance the antioxidant capacity of the gastrointestinal system in rats. These probiotics could be used as important adjuvants to maintain balance in the gut, although more studies are required to demonstrate their efficacy in humans.