Discontinuing Lactobacillus reuteri: Safety and Cancer Risk
You can discontinue Lactobacillus reuteri immediately without tapering, and there is no evidence that long-term probiotic use increases gastrointestinal or colon cancer risk.
Immediate Discontinuation is Safe
- Probiotics like L. reuteri do not require tapering and can be stopped abruptly without adverse effects. 1
- L. reuteri does not permanently colonize the gastrointestinal tract—after stopping a 2-week course, the bacterium disappears from the oral cavity within 1 week in 92% of subjects and is completely undetectable after 5 weeks. 2
- Unlike medications such as proton pump inhibitors (which may cause rebound acid hypersecretion requiring gradual tapering), probiotics do not cause physiological dependence or withdrawal symptoms. 3
No Cancer Risk from Long-Term Use
- There is no evidence linking probiotic use, including L. reuteri, to increased risk of gastrointestinal or colon cancer. 1
- A comprehensive safety review of 622 probiotic studies found no statistically significant increased risk of adverse events with probiotic use compared to placebo (RR 1.00; 95% CI: 0.93-1.07). 1
- The primary safety concerns with probiotics are rare cases of fungemia or bacteremia in severely immunocompromised or critically ill patients—not cancer development. 1
Safety Profile of L. reuteri
- L. reuteri has been extensively studied and is considered safe and well-tolerated in both children and adults. 4, 5, 6
- In a randomized controlled trial of hospitalized adults receiving L. reuteri for 4 weeks, the probiotic was safe with no significant adverse events reported. 6
- A 2024 pediatric trial of L. reuteri NCIMB 30351 in 90 infants for 25 days reported no adverse events. 5
Clinical Context
- The only populations requiring caution with probiotics are those with severe immunocompromise, central venous catheters, or critical illness—and even in these groups, controlled trials have not shown statistically increased adverse event rates. 1
- For healthy individuals or those with routine gastrointestinal conditions who have been taking L. reuteri, discontinuation carries no risk and requires no special precautions. 1, 2