['The aim of the present study was to investigate the effect of a probiotic beverage on gastrointestinal symptoms in patients with chronic constipation.', 'A double-blind, placebo-controlled, randomized study was conducted over a four-week period in patients with symptoms of chronic constipation (n=70). To all patients, 65 mL/day of a probiotic beverage containing Lactobacillus casei Shirota (LcS) or a sensorially identical placebo was administered. Patients completed a questionnaire on gastrointestinal symptoms, well-being and stool habits and underwent a medical examination weekly. Severity of constipation, flatulence and bloating was summarized into four categories (severe, moderately severe, mild and no symptoms).', 'The consumption of LcS resulted in a significant improvement in self-reported severity of constipation and stool consistency, starting in the second week of the intervention phase (P<0.0001). Severe and moderately severe constipation was observed less in the LcS group. The occurrence and degree of flatulence or bloating sensation did not change. In the final examination, 89% of the LcS group and 56% of the placebo group showed a positive effect of their beverage on constipation (P=0.003). No adverse reactions were reported.'] Does probiotic beverage containing Lactobacillus casei Shirota improve gastrointestinal symptoms in patients with chronic constipation?