Do probiotics help with inflammation? What the research does and doesn't show

The evidence does not support probiotics as an anti-inflammatory supplement for people in general. In healthy working adults, a pooled analysis of randomized trials found no significant effect on C-reactive protein, a common inflammation marker. Results in rheumatoid arthritis and gut disease are mixed, low in certainty and specific to the trial's strain.

What the evidence doesn't support

• No significant effect on inflammation in healthy people: in 12 trials of 3,350 healthy working adults, probiotics had no significant effect on CRP, though they did on some self-reported mood measures.
• Not an arthritis treatment: in rheumatoid arthritis, CRP fell, but after excluding high-risk-of-bias trials disease activity did not differ from placebo, and two studies in spondyloarthritis showed no benefit.
• Not a gut-inflammation treatment: in inflammatory bowel disease there was a remission signal in ulcerative colitis only, and none in Crohn's disease, with low certainty.
• Not one general result: marker, population, strain and dose all differ between trials.

What the trials found

Healthy adults

A 2026 systematic review and meta-analysis of 12 randomized trials in 3,350 healthy employed adults found a modest reduction in self-reported depression, anxiety and stress symptoms (SMD -0.21) and cortisol (SMD -0.26), and no significant effect on C-reactive protein. The authors attributed heterogeneity to differing strains, doses and durations.

Rheumatoid arthritis and spondyloarthritis

A review of randomized trials in 344 people with rheumatoid arthritis (eight studies) and 197 with spondyloarthritis (two studies) found CRP fell by 3.04 mg/L (95% CI -4.47 to -1.62) in rheumatoid arthritis. However, after excluding high-risk-of-bias trials there was no difference from placebo in the DAS28 disease activity score (SMD -0.54, 95% CI -1.94 to 0.85). The two spondyloarthritis studies showed no efficacy. Strains varied (five studies used Lactobacillus, one Bacillus coagulans, the rest mixtures) and follow-up ran from 8 weeks to a year. The authors said lack of evidence and heterogeneity do not allow them to propose probiotics to patients with inflammatory arthritis.

Inflammatory bowel disease

The 2024 overview and meta-analysis of 45 randomized trials found odds of clinical remission of 2.00 (95% CI 1.28 to 3.11) in ulcerative colitis and 1.61 (95% CI 0.21 to 12.50, not significant) in Crohn's disease. There was no better endoscopic outcome and no lower recurrence in Crohn's disease. Certainty was low, and these were people under medical care.

Diverticular disease

In three studies of acute uncomplicated diverticulitis, CRP fell after probiotics, but baseline levels and timing varied too much to pool, and the review rated certainty low to very low.

Questions people ask

Do probiotics reduce inflammation?

The only pooled result in healthy adults found no significant change in CRP. In specific diseases some trials reported lower markers, with the limits above.

Are probiotics good for gut inflammation?

See the IBD result: a signal in ulcerative colitis, none in Crohn's disease, low certainty. Gut inflammation is diagnosed and managed by a doctor. More in probiotics and gut conditions.

Do probiotics help rheumatoid arthritis?

A lower CRP in some trials, but no difference in disease activity once higher-risk trials were excluded. Do not stop or change arthritis care on the strength of this.

Also: probiotics benefits and probiotics and stress.

When to talk to a doctor

A supplement is not a treatment for inflammation, arthritis or bowel disease. Joint swelling, morning stiffness, blood in stool, persistent diarrhea, fever or unexplained weight loss need a medical assessment. Ask a doctor or pharmacist before starting a probiotic if you have a weakened immune system, are pregnant or nursing, or take prescription medicine.