Research review
Does acidophilus help with IBS? What the research does and doesn't show
The evidence doesn't support acidophilus as a treatment for IBS, GERD, ulcerative colitis or diverticulitis. One large trial of a named strain found reduced abdominal pain in IBS specifically; we found no trial testing acidophilus for the other three conditions.
The evidence doesn't support acidophilus as a treatment for IBS, GERD, ulcerative colitis or diverticulitis. This page focuses on IBS, where the research actually exists: one large trial of a named strain found reduced abdominal pain and symptom severity. We found no trial testing acidophilus for GERD, ulcerative colitis or diverticulitis specifically, so those three remain unanswered, not answered no.
What the evidence doesn't support
It doesn't support acidophilus as a treatment, cure or replacement for medical management of IBS, GERD, ulcerative colitis or diverticulitis. Even the largest trial below, on IBS, tested symptom reduction in people already diagnosed with the condition — it doesn't establish that acidophilus prevents IBS, or that it works the same way for someone who hasn't been diagnosed. For GERD, ulcerative colitis and diverticulitis, we didn't find a trial of Lactobacillus acidophilus at all, so there's no research to weigh either way on this ingredient for those three conditions.
What the trials found
A large randomized, double-blind, placebo-controlled trial gave 330 adults (18-70) with Rome IV-diagnosed IBS either placebo, the DDS-1 strain of L. acidophilus alone (10 billion CFU/day), or a Bifidobacterium strain, for 6 weeks. The DDS-1 group had significantly less abdominal pain than placebo, and a significantly better overall IBS symptom severity score, with improvements across pain, bloating, bowel habits and quality-of-life sub-scores; 52.3% of the DDS-1 group were classified as significant responders. This is a large trial with a clear result for one named, single strain — but two of the study's authors are employees of the company that sells DDS-1, which is worth knowing when weighing the result.
A separate trial gave 60 adults with non-constipation functional bowel disorders a two-strain combination — L. acidophilus NCFM plus B. lactis Bi-07 — for 8 weeks, and found reduced bloating severity versus placebo at both 4 and 8 weeks, with similar results in the IBS subgroup specifically. A smaller, related trial isolated NCFM alone in 20 women with mild-to-moderate abdominal pain for 21 days and found it changed a pain-related receptor in colon tissue, but the trial was explicitly too small to say whether that translated into symptom relief.
None of these trials addressed GERD, ulcerative colitis or diverticulitis. Those are different conditions from IBS. GERD involves the esophagus. Ulcerative colitis is a separately diagnosed inflammatory bowel disease. Diverticulitis is acute inflammation in pouches of the colon wall. A finding for IBS doesn't transfer to any of them.
Questions people ask
Is acidophilus good for IBS?
A large, single-strain trial (DDS-1, 10 billion CFU/day for 6 weeks) found reduced abdominal pain and overall symptom severity versus placebo in adults with Rome IV-diagnosed IBS. That's a specific strain and dose, not "acidophilus" as a general category, and the trial's authors included employees of the strain's manufacturer.
Is acidophilus good for GERD?
We didn't find a trial testing Lactobacillus acidophilus against GERD or reflux symptoms, so there's no research to report on this specific question.
Does acidophilus help with ulcerative colitis or diverticulitis?
We didn't find a trial testing Lactobacillus acidophilus against either condition. Both are diagnosed medical conditions that require evaluation and treatment from a doctor, and a probiotic supplement isn't established as a treatment for either.
Will acidophilus help with IBS if I've never been diagnosed?
The trial above enrolled people already diagnosed with IBS under Rome IV criteria; it doesn't tell you what acidophilus would do for undiagnosed digestive symptoms. Persistent digestive symptoms are worth discussing with a doctor to get a diagnosis first.
When to talk to a doctor
Persistent or severe digestive symptoms — abdominal pain, changes in bowel habits, heartburn, rectal bleeding — are worth evaluating with a doctor rather than self-treating with a supplement. Acidophilus is not a treatment for IBS, GERD, ulcerative colitis or diverticulitis, and the IBS trial above studied symptom reduction in an already-diagnosed population, not a cure. If you're on medication for a digestive condition, or have a diagnosed inflammatory bowel disease, talk to a doctor before adding any probiotic.
Related reading: acidophilus: what the research shows and acidophilus side effects.
Sources
- Lactobacillus acidophilus DDS-1 and Bifidobacterium lactis UABla-12 Improve Abdominal Pain Severity and Symptomology in Irritable Bowel Syndrome: Randomized Controlled Trial A large (330-person), 6-week randomized trial of the DDS-1 strain of L. acidophilus alone, at 10 billion CFU/day, found significantly reduced abdominal pain and overall IBS symptom severity versus placebo, in adults diagnosed with IBS under Rome IV criteria; the trial was funded by, and two authors were employed by, the company that sells the DDS-1 strain.
- Probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 versus placebo for the symptoms of bloating in patients with functional bowel disorders: a double-blind study A two-strain combination of L. acidophilus NCFM and B. lactis Bi-07, at a combined 2x10^11 CFU/day for 8 weeks, reduced bloating versus placebo in adults with functional bowel disorders — but this tested two species together, not acidophilus alone.
- Lactobacillus acidophilus NCFM affects colonic mucosal opioid receptor expression in patients with functional abdominal pain - a randomised clinical study A small human trial found the NCFM strain of L. acidophilus alone changed a pain-related receptor in colon tissue, but the trial was too small to say whether it actually improved symptoms.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.