Can stomach pain be caused by taking probiotics?

Can Probiotics Cause Stomach Pain?

Yes, probiotics can cause stomach pain and abdominal discomfort in some individuals, particularly when taken in large doses or in patients with underlying gastrointestinal sensitivity such as irritable bowel syndrome (IBS). 1

Mechanism of Probiotic-Related Abdominal Pain

Probiotics may induce abdominal symptoms through several pathways:

• Osmotic effects in the intestinal lumen leading to increased fluid retention and distension 1
• Fermentation in the colon producing gas and causing bloating, which can manifest as pain 1
• Individual sensitivity factors, particularly in patients with pre-existing IBS or gastroesophageal reflux disease, making them more susceptible to probiotic-induced discomfort 1

Dose-Dependent Effects

The likelihood and severity of abdominal pain correlates with probiotic dosage:

• Large doses are more likely to cause symptoms, including abdominal pain and diarrhea 1
• Lower starting doses (1 × 10⁸ CFU per day) are better tolerated and should be the initial approach 2
• Tolerance improves with chronic consumption as the gut adapts to the probiotic supplementation 1

Clinical Context: When Pain Occurs vs. When It Improves

The relationship between probiotics and abdominal pain is paradoxical and depends on the clinical scenario:

Probiotics may worsen pain in:

• Patients without functional GI disorders who take high doses 1
• Individuals with heightened visceral sensitivity 1
• Those with gastroesophageal reflux when consuming large daily doses 1

Probiotics may improve pain in:

• IBS patients using specific strains like Lactobacillus, Bifidobacterium, or combination probiotics, which reduce global symptoms and abdominal pain (RR 0.75-0.80) 3
• Children with functional abdominal pain treated with Lactobacillus reuteri DSM 17938, showing decreased pain intensity (mean difference -1.24,95% CI -2.35 to -0.13) 4
• Patients receiving pelvic radiotherapy, where probiotics significantly reduce abdominal pain incidence and severity 3

Management Algorithm

If a patient develops stomach pain after starting probiotics:

1. Discontinue the probiotic immediately to assess if symptoms resolve 3, 5
2. If symptoms persist beyond 48-72 hours, evaluate for other causes of abdominal pain
3. If symptoms resolve, consider reintroduction at a lower dose (starting at 1 × 10⁸ CFU/day) 2
4. Monitor for 12 weeks maximum—if no benefit is seen, permanently discontinue 3, 5

Important Caveats

• The British Society of Gastroenterology notes that adverse event rates are similar between probiotic and placebo arms in IBS trials, suggesting that when pain occurs, it may be coincidental rather than causative 3
• Strain-specific effects matter: Some strains like Saccharomyces boulardii showed no significant difference from placebo for abdominal pain 6, while others like Lactobacillus reuteri DSM 17938 demonstrated benefit 4
• Very sick or immunocompromised patients are at higher risk for rare infectious complications, though these are exceedingly uncommon 1
• Bloating and gaseousness are more common than frank abdominal pain with probiotic use 1

When to Avoid Probiotics

Do not recommend probiotics for patients who:

• Have experienced worsening symptoms with previous probiotic trials 6
• Report severe or progressive abdominal pain requiring evaluation for organic disease
• Are critically ill or severely immunocompromised without specific indication 1