Key clinical point: Irritable bowel syndrome symptoms were improved in about one-third of patients who took an inactivated bacterial treatment, pointing the way to a therapeutic path that could avoid some risks of live probiotic use.

Major finding: Within the Bifidobacterium bifidum group, 74 patients (34%) reached this endpoint, compared with 43 (19%) of those in the placebo group, for a risk ratio of 1.7 (P = .0007). Patients had no serious adverse events from the oral therapy, which they took in the form of two capsules daily for 8 weeks, and participants found both the inactivated Bifidobacterium treatment and placebo tolerable overall.

Study details: A randomized, double-blind, placebo-controlled trial of a heat-inactivated nonviable Bifidobacterium given to 221 people who received the Bifidobacterium, and 222 who received placebo capsules.

Disclosures: The study was funded by Synformulas. Dr. Andresen reported financial relationships with several pharmaceutical companies. Dr. Talley reported financial relationships with several pharmaceutical and nutritional companies.