Fumonisin B1 (FB1) is a carcinogenic (Class 2B) mycotoxin produced by Fusarium fungi and is responsible for several types of mycotoxicoses in animals and humans. Lactobacillus paracasei (LP), as a probiotic, is known to impart a wide range of advantageous effects on host health. The objective of the current study was to evaluate if LP (type BEJ01) isolated from Tunisian artisanal butter, could potentially help protect a host against intestinal alterations caused by exposure to FB1. Here, adult male Balb/c mice were randomly assigned to four groups, i.e., control (vehicle only), treated with FB1 (100 µg/kg BW), LP (2 × 109 CFU/ml [≈ 2 mg/kg BW]) and FB1 (100 µg/kg BW) + LP (2 × 109 CFU/ml) and treated per os daily for 10 days. At 24 hr after the final treatment, mice were euthanized and their jejunum harvested for examination of intestinal alterations induced by the FB1. The data showed that a variety of negative effects in jejunal tissue were induced by the FB1, including DNA fragmentation, oxidative stress, apoptotic cell death, and histopathological alterations. The results also showed that co-treatment of LP with FB1 was able to mitigate the harmful FB1 effects. LP alone imparted no damage to jejunal tissues. These results show that apart from potential use as a bio-preservative for extending the shelf-life of food and feeds, LP may also provide a benefit of helping prevent untoward effects from a potent mycotoxin like FB1.