Background: The efficacy of some probiotic strains for the management of lactose intolerance remains to be established. Aim :To evaluate the effects of a 4-week consumption of a probiotic product containing Lactobacillus casei Shirota and Bifidobacterium breve Yakult (10(7)-10(9) CFU of each strain) on symptoms and breath hydrogen exhalation after a lactose load in lactose-intolerant patients and whether the beneficial results persisted after probiotic discontinuation. Methods: Twenty-seven patients with lactose maldigestion and intolerance participated in this study, which comprised 4 hydrogen breath tests: baseline condition (20 g lactose), after lactase ingestion (9000 FCC units), at the end of 4-week probiotic supplementation, and a follow-up test performed 3 months after probiotic discontinuation. For each test, the area under the breath hydrogen concentration vs time curve (AUC(180 min)) was calculated, and symptom scores were recorded. Results: The probiotic combination significantly reduced symptom scores (P < .01) and breath hydrogen AUC (P = .04) compared with the baseline condition. The comparison with the lactase test showed that symptom scores were similar (P > .05), despite the significantly higher (P = .01) AUC values after probiotic use. In the follow-up test, symptom scores and breath hydrogen AUC values remained similar to those found at the end of probiotic intervention. Conclusion: Four-week consumption of a probiotic combination of L casei Shirota and B breve Yakult seems to improve symptoms and decrease hydrogen production intake in lactose-intolerant patients. These effects may persist for at least 3 months after suspension of probiotic consumption. (Nutr Clin Pract. 2012;27:247-251)272247251