Research review
Do probiotics help with seizures or Parkinson's? What the research does and doesn't show
Small trials reported fewer seizures with a probiotic added to usual care and more bowel movements in Parkinson's, but no difference in Parkinson's motor scores.
The evidence does not support probiotics as a treatment for epilepsy or Parkinson's disease. Small trials reported fewer seizures when a probiotic was added to usual care, and more bowel movements in Parkinson's, but no difference in Parkinson's motor scores. The evidence is limited and these are conditions for a neurologist, not a supplement.
What the evidence doesn't support
- No trial showed a probiotic replacing or reducing epilepsy care: the trials tested probiotics added to usual treatment, and the authors called the evidence limited.
- Slowing Parkinson's. In 11 trials of 756 people there was no significant difference in motor (MDS-UPDRS III) scores versus placebo (SMD -0.09, 95% CI -0.35 to 0.16).
- A named strain or dose. The abstracts we verified do not give one that is established.
What the trials found
Epilepsy
A 2025 meta-analysis of six randomized trials in 656 people with epilepsy compared a probiotic combination added to usual care with usual care alone: clinical efficacy rate was higher (RR 1.16, 95% CI 1.09 to 1.24) and seizure frequency lower (mean difference -1.97), with no difference in adverse reactions. The authors cited limited sample size and methods and called for validation. A separate placebo-controlled trial in 70 people with temporal lobe epilepsy found fewer seizures with probiotics than placebo over a 12-week course, with no change in cognition and lower anxiety and depression scores. Strain and dose are not stated in its abstract.
Parkinson's disease
The review of 11 randomized placebo-controlled trials in 756 people with Parkinson's found probiotics increased complete bowel movements per week and improved a constipation quality-of-life score, but did not significantly improve stool traits or straining. A second review of four trials (287 people) found about one more bowel movement a week (weighted mean difference 1.02), high heterogeneity, low-quality evidence and no significant change in stool consistency or pain, and concluded evidence was insufficient to support use of probiotics for constipation in Parkinson's. Strains varied.
Questions people ask
Do probiotics help with seizures?
Some small trials reported fewer seizures with a probiotic alongside usual care. The evidence is limited, and no one should change seizure medicine on this basis.
Are probiotics good for Parkinson's patients?
They have been studied for constipation, a common problem, with small gains in bowel movement frequency and no difference in motor scores. Talk to the treating team before adding any supplement.
Related: probiotics benefits and who should not take probiotics.
When to talk to a doctor
A probiotic is not a treatment for epilepsy or Parkinson's disease. Any seizure, new tremor, stiffness or change in movement needs a doctor, and anyone with a neurological condition should ask their doctor or pharmacist before adding a supplement, particularly with a weakened immune system or prescription medicine.
Sources
- Probiotics in epilepsy treatment: a meta-analysis of efficacy and safety A 2025 review of six small trials found fewer seizures when a probiotic was added to usual care, with the authors calling the evidence limited.
- Effects of long-term supplementation of probiotics on cognitive function and emotion in temporal lobe epilepsy In 70 people with temporal lobe epilepsy, 12 weeks of probiotics was followed by fewer seizures than placebo, but cognition did not differ.
- Efficacy of probiotic supplements on Parkinson's disease: A systematic review and meta-analysis A review of 11 trials in Parkinson's disease found more bowel movements with probiotics but no difference in motor symptom scores.
- Probiotics for constipation in Parkinson's: A systematic review and meta-analysis of randomized controlled trials A review of four trials found about one more bowel movement a week with probiotics in Parkinson's disease, with low-quality evidence and no change in stool consistency.
*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.