Lactobacillus bulgaricus

Lactobacillus delbrueckii subsp. bulgaricus · Lactobacillus delbrueckii · L. bulgaricus · Lactobacillus bulgaricus GLB44

Snapshot

Indications	Contraindications
Helicobacter pylori eradication¹ Blood triglycerides² Gastrointestinal symptoms³ Gut immune function³ Sleep quality³	Immune-compromised conditions⁴ Milk allergy⁵

Lactobacillus bulgaricus (Lactobacillus delbrueckii subsp. bulgaricus) is a traditional yogurt starter that adheres to intestinal cells and supports gut microbial balance and mucosal immune responses. People take it for digestive symptoms, as a companion to Helicobacter pylori eradication regimens, and for blood triglycerides. It usually appears in multistrain products.

Evidence is mixed. A meta-analysis of Lactobacillus acidophilus plus L. bulgaricus found little or no clinical benefit for diarrhea⁶. A synbiotic in critically ill patients altered upper gastrointestinal flora without measurable clinical benefit⁷. In elderly hip-fracture patients, a fermented milk product containing L. bulgaricus did not reduce Clostridium difficile associated diarrhea⁸. Adding L. delbrueckii subsp. bulgaricus and Streptococcus thermophilus to triple therapy raised Helicobacter pylori eradication rates in a randomized trial¹. Products listing L. bulgaricus number in the thousands, as capsules, powders, and tablets; see Form comparison.

Health Canada lists immune-compromised conditions as a contraindication on licensed products, and its labels ask for a practitioner's advice for fever, vomiting, bloody diarrhoea, or severe abdominal pain⁴. United States labels warn of milk content, which matters for milk-allergic patients⁵.

Last updated October 17, 2026. Read how we make monographs.

In the full monograph

26 sources, 17 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources