Probiotics (e.g. Align, VSL#3, Florastor)

How it works: We are not exactly sure how probiotics work in IBS. They could act by reducing gas production, decreasing inflammation or modifying gut motility and/or sensation.

Which symptoms does it help: Overall IBS symptoms, especially flatulence, bloating, pain.

How long it takes to see a benefit: Within 4 weeks.

FDA approved: Not regulated by the FDA as drugs.

Dosage: Many different doses and formulations.

Special considerations or risks: Discuss with your doctor if you have a suppressed or deficient immune system.

Most common side effects: Initially there may be some bloating and discomfort as your intestines “adjust” to the new bacteria but that should be short-lived. Generally safe.

Recommendation: ACG does not recommend routinely using probiotics to treat IBS, because data from clinical studies have been inconsistent.