D-Lactic Acidosis, "Brain Fog" and Probiotics in Short Bowel Syndrome and SIBO
What D-lactic acidosis is, why it is linked to short bowel syndrome, what case reports say about probiotics, and what is not known about "brain fog" and SIBO.
Content last updated . This page has not been medically reviewed.
Urgent first
D-lactic acidosis is a rare condition mostly described in people with short bowel syndrome (SBS). If someone with SBS develops new neurological symptoms, treat it as urgent and get medical care; in the US call 911 for an emergency. One reported child presented with intermittent ataxia (unsteady movement). [1] Do not start a probiotic with short bowel syndrome without the treating team's approval.What it is
Case-report authors describe D-lactic acidosis as an uncommon cause of acidosis in patients with short bowel syndrome: a reduced absorbing surface leads to carbohydrate malabsorption, abnormal bacteria in the colon ferment those carbohydrates, and D-lactate rises. [2] A pediatric case report adds that an increase in D-lactate-producing bacteria can lead to D-lactic acidosis, also called D-lactate encephalopathy. [3] It should be suspected in SBS patients with typical neurological symptoms without another cause; treatment involves correcting the acidosis and managing bacterial overgrowth, with non-absorbable antibiotics. [2] That is clinician-led care.SIBO (small intestinal bacterial overgrowth) means an abnormal proliferation of bacteria in the small intestine. [4] SBS can predispose children to SIBO, and severe cases can lead to complications such as D-lactic acidosis. [4]
What the reports say about probiotics
| Question | What the source found | Label |
|---|---|---|
| Can a probiotic be linked to D-lactic acidosis? | A 5-year-old girl with SBS developed D-lactic acidosis after being given a probiotic preparation at twice the regular amount; the authors judged the probiotic the likely cause and concluded probiotics should be avoided in SBS. [1] | Limited evidence (one case) |
| Can a probiotic ever help? | A boy with SBS and recurrent episodes despite cycling antibiotics was given a probiotic mix; D-lactate-producing Lactobacillus strains disappeared within weeks and he stayed stable for over a year. [3] | Limited evidence (one case, no comparison) |
| What do reviews say? | A systematic review in children with SBS found no randomized trials of probiotics, one small crossover trial, and case reports with both benefits and harms (Lactobacillus sepsis, n = 3; d-lactic acidosis, n = 2); it concluded evidence is insufficient. [5] | Insufficient evidence |
| SIBO in SBS | A 2025 review said adjunctive therapies including probiotics show promise but require further validation in children. [4] | Insufficient evidence |
The two single cases point in opposite directions, which is exactly why they cannot guide choices: each involved a particular product, a particular child and no comparison group. Strain-level details are in Strain specificity.
"Brain fog"
Proper evidence not found that probiotics cause general "brain fog" in people without short bowel syndrome. We searched PubMed for D-lactic acidosis with probiotics, D-lactate encephalopathy and short bowel syndrome, and SIBO with D-lactic acidosis. Every D-lactic acidosis report we read involved short bowel syndrome. Fatigue or mental cloudiness has many causes, so ongoing symptoms deserve a clinician's assessment rather than self-treatment. Related claims: Probiotics, mood and anxiety.Questions for the care team
- Is a probiotic appropriate for my particular bowel anatomy?
- Which signs should make me call right away?
- Does my antibiotic or nutrition plan interact with a probiotic?
Frequently asked questions
What is D-lactic acidosis?
An uncommon acidosis seen in short bowel syndrome, in which abnormal colon bacteria ferment carbohydrates and D-lactate rises. [2]
Can probiotics cause it?
One case report linked it to a probiotic preparation in a child with SBS; another found a probiotic mix suppressed D-lactate-producing bacteria. Reviews call the evidence insufficient. [1][3][5]
Do probiotics cause brain fog?
Proper evidence not found.
Is it a risk if I do not have short bowel syndrome?
Proper evidence not found; all reports we read involved SBS.
Are probiotics recommended for SIBO in short bowel syndrome?
A 2025 review said they show promise but need validation in children. [4]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
How to read the evidence labels
Labels used on this page: limited evidence (case reports and small reviews) and Proper evidence not found.
References
- Munakata S, et al. A case of D-lactic acid encephalopathy associated with use of probiotics. Brain Dev. 2010;32(8):691-4. Single case report; abstract read 2026-10-22.
- Carrillo-Lopez E, et al. Short bowel syndrome and d-lactic acidosis: a case report with supplemental home parenteral nutrition and teduglutide. Endocrinol Diabetes Nutr. 2025;72(3):101535. Abstract read 2026-10-22.
- Yilmaz B, et al. D-lactic Acidosis: Successful Suppression of D-lactate-Producing Lactobacillus by Probiotics. Pediatrics. 2018;142(3):e20180337. Single case report; abstract read 2026-10-22.
- DeGonza H, et al. Small Intestinal Bacterial Overgrowth in Children with Short Bowel Syndrome. Children (Basel). 2025;12(11):1550. Review; abstract read 2026-10-22.
- Reddy VS, et al. Role of probiotics in short bowel syndrome in infants and children: a systematic review. Nutrients. 2013;5(3):679-99. Abstract read 2026-10-22.