Background: The combination of Lactobacillus fermentum and Lactobacillus delbrueckii (Lactobacillus LB) has proven to be effective and safe for the treatment of acute diarrhea in children. Also, a clinical trial in adult patients with chronic diarrhea showed a reduction in the number of daily stools. However, the evidence is not enough regarding the efficacy and safety of Lactobacillus LB for the treatment of patients with irritable bowel syndrome with a predominance of diarrhea (IBS-D).~Justification for this study: Lactobacillus LB could be a promising treatment for patients with IBS-D; nevertheless, the scientific evidence in this context is limited and it is not recent. Therefore, is necessary to explore the efficacy and safety of Lactobacillus LB in patients with IBS-D according to Rome IV criteria.~Hypothesis: Lactobacillus LB is useful to decrease the frequency and improve the stools consistency of patients diagnosed with IBS-D by Rome IV criteria.~Primary Outcome: To compare the treatment with Lactobacillus LB at two different doses: a) 20,000 million / day, vs. b) 10,000 million / day; and to determine if one of them is better than c) placebo, to decrease the frequency (weekly average of the number of stools/day) in patients diagnosed with IBS-D by Rome IV criteria.~Design of the study: Clinical trial, randomized, double-blind, placebo-controlled.~Keywords: irritable bowel syndrome with diarrhea, Lactobacillus LB, treatment, efficacy, safety.
Background: The combination of Lactobacillus fermentum and Lactobacillus delbrueckii (Lactobacillus LB) has proven to be effective and safe for the treatment of acute diarrhea in children. Also, a clinical trial in adult patients with chronic diarrhea, showed a reduction in the number of daily stools. However, the evidence is not enough regarding the efficacy and safety of Lactobacillus LB for treatment of patients with irritable bowel syndrome with predominance of diarrhea (IBS-D).~Justification for this study: Lactobacillus LB could be a promising treatment for patients with IBS-D; nevertheless, the scientific evidence in this context is limited and it is not recent. Therefore, is necessary to explore the efficacy and safety of Lactobacillus LB in patients with IBS-D according to Rome IV criteria.~Hypothesis: Lactobacillus LB is useful to decrease the frequency and improve the stools consistency of patients diagnosed with IBS-D by Rome IV criteria.~Primary Outcome: To compare the treatment with Lactobacillus LB at two different doses: a) 20,000 million / day, vs. b) 10,000 million / day; and to determine if one of them is better than c) placebo, to decrease the frequency (weekly average of the number of stools/day) in patients diagnosed with IBS-D by Rome IV criteria.~Design of the study: Clinical trial, randomized, double-blind, placebo-controlled.~Keywords: irritable bowel syndrome with diarrhea, Lactobacillus LB, treatment, efficacy, safety.