Lactiplantibacillus plantarum PS128 is a specific strain of Lactiplantibacillus plantarum, a bacterium of the genus Lactobacillus .

Lactiplantibacillus plantarum is a diverse species of lactic bacterium found in a wide range of ecological niches including plant substrates, meat, milk, as well as in the gastrointestinal tract of humans.

Lactic bacteria are gram-positive, oxygen-tolerant anaerobes that have been used in food fermentation for hundreds of years.

[1] Lactiplantibacillus plantarum is "generally recognized as safe".

[3] A study on Rett syndrome patients found that probiotic Lactiplantibacillus plantarum PS128 supplementation was safe, well-tolerated, and showed promising improvements in cognitive development and dystonia, suggesting potential as a complementary therapy for Rett syndrome.