Background & aims: Probiotics can maintain ulcerative colitis (UC) in remission effectively, but little is known of their ability to induce remission. We conducted a multicenter, randomized, double-blind, placebo-controlled trial of a high-potency probiotic, VSL#3, for the treatment of mild-to-moderately active UC.

Methods: Adult patients with mild-to-moderate UC were assigned randomly to groups that were given 3.6 x 10(12) CFU VSL#3 (n = 77) or placebo (n = 70), twice daily for 12 weeks. The primary end point was a 50% decrease in the Ulcerative Colitis Disease Activity Index (UCDAI) at 6 weeks. The secondary end points included remission by 12 weeks and reduction in total individual UCDAI parameters from baseline at 12 weeks. Intention-to-treat analysis was performed.

Results: At week 6, the percentage of patients with an improvement in UCDAI score that was greater than 50% was significantly higher in the group given VSL#3 (25; 32.5%) than the group given placebo (7; 10%) (P = .001). At week 12, there were 33 patients given VSL#3 (42.9%) who achieved remission, compared with 11 patients given placebo (15.7%) (P < .001). Furthermore, significantly more patients given VSL#3 (40; 51.9%) achieved a decrease in their UCDAI that was greater than 3 points, compared with those given placebo (13; 18.6%) (P < .001). The VSL#3 group had significantly greater decreases in UCDAI scores and individual symptoms at weeks 6 and 12, compared with the placebo group.

Conclusions: VSL#3 is safe and effective in achieving clinical responses and remissions in patients with mild-to-moderately active UC.