According to Gram Research analysis, a 2026 laboratory study found that fermented liquid from Lactiplantibacillus plantarum S61 bacteria killed breast cancer cells while leaving healthy cells largely unharmed, with the bacteria grown on xylooligosaccharides showing the strongest effect—blocking inflammation by 88.7%, nearly matching the prescription drug diclofenac. However, this research was conducted only in test tubes and cell cultures, not in living organisms or people, so it remains very early-stage and far from any potential medical treatment.
Researchers studied a type of beneficial bacteria called Lactiplantibacillus plantarum S61 to see if it could fight cancer and reduce inflammation. When grown on a special plant fiber called xylooligosaccharides, the bacteria produced compounds that killed breast cancer cells in lab tests while leaving healthy cells mostly unharmed. The fermented liquid also reduced inflammation as effectively as some anti-inflammatory medicines. While these results are exciting, the research was done in test tubes and cells, not in people, so much more testing is needed before this could become a treatment.
Key Statistics
A 2026 laboratory study found that Lactiplantibacillus plantarum S61 fermented on xylooligosaccharides produced vitamin B2 at 8.05 mg/L and blocked inflammation by 88.7% at 400 micrograms per milliliter, nearly matching the prescription anti-inflammatory drug diclofenac’s 91.44% effectiveness.
According to research reviewed by Gram, the xylooligosaccharide-fermented bacterial liquid required 198.55-200.80 micrograms per milliliter to kill 50% of breast cancer cells but needed 862.16 micrograms per milliliter to harm healthy immune cells at the same rate, showing roughly 4-fold selectivity for cancer cells.
A 2026 in vitro study demonstrated that Lactiplantibacillus plantarum S61 fermented on xylooligosaccharides produced vitamin B12-like compounds at 0.24 mg/L while exhibiting dose-dependent killing of MCF-7 and MDA-MB-231 breast cancer cell lines with minimal toxicity to normal immune cells.
The Quick Take
- What they studied: Whether a probiotic bacteria could produce compounds that fight inflammation and kill cancer cells when grown on different types of food sources
- Who participated: This was laboratory research using cancer cells (breast cancer lines MCF-7 and MDA-MB-231) and healthy immune cells, not human volunteers
- Key finding: Bacteria grown on xylooligosaccharides produced compounds that killed cancer cells at doses that were much safer for healthy cells, with anti-inflammatory effects comparable to prescription pain relievers
- What it means for you: This is early-stage research showing potential, but it was done in test tubes and cells only. Much more research in animals and eventually people would be needed before this could become a real cancer treatment
The Research Details
Scientists grew Lactiplantibacillus plantarum S61 bacteria in two different environments: one with glucose (regular sugar) and one with xylooligosaccharides (a plant fiber). They collected the liquid left behind after removing the bacteria cells and tested what compounds it contained. They then tested this liquid on cancer cells and healthy immune cells in petri dishes to see if it could kill cancer cells without harming healthy ones. They also tested whether the liquid could reduce inflammation using a standard laboratory test that measures how well a substance prevents protein damage.
This research approach is important because it tests whether the byproducts bacteria create (called postbiotics) have healing properties. By comparing two different growth environments, the researchers could see which conditions made the bacteria produce the most beneficial compounds. Testing on both cancer and healthy cells shows whether a treatment might be selective—meaning it targets cancer without harming the body.
This is laboratory research published in a peer-reviewed journal, which means other scientists reviewed it before publication. However, because it was done only in test tubes and cell cultures, not in living organisms or people, the results are preliminary. The measurements were precise and included error margins, showing careful scientific work. The selectivity between cancer and healthy cells is a positive sign, but lab results don’t always translate to real-world effectiveness.
What the Results Show
The bacteria produced significant amounts of B vitamins when grown on both sugar sources. When grown on xylooligosaccharides, the bacteria produced 8.05 mg/L of vitamin B2 and 0.24 mg/L of vitamin B12-like compounds. The fermented liquid from xylooligosaccharide growth showed the strongest anti-inflammatory effect, blocking 88.7% of protein damage at a dose of 400 micrograms per milliliter—nearly as effective as the prescription anti-inflammatory drug diclofenac (91.44% blocking). The glucose-fermented liquid was less effective at 71.1% blocking. Both fermented liquids killed breast cancer cells in a dose-dependent way, meaning higher doses killed more cancer cells. Importantly, the xylooligosaccharide-fermented liquid killed cancer cells at much lower doses than it took to harm healthy immune cells, showing selectivity.
The xylooligosaccharide-fermented supernatant required 198.55 micrograms per milliliter to kill 50% of MCF-7 breast cancer cells and 200.80 micrograms per milliliter for MDA-MB-231 cells, but needed 862.16 micrograms per milliliter to harm healthy immune cells at the same rate. This means the treatment was roughly 4 times safer for healthy cells than for cancer cells. The glucose-fermented version showed similar patterns but was less selective. These findings suggest the bacteria’s metabolites could potentially be developed as natural compounds with dual benefits.
This research builds on growing interest in postbiotics—the compounds bacteria produce—as potential health agents. Previous studies have shown that Lactiplantibacillus plantarum has anti-inflammatory properties, but this study is notable for demonstrating selective anticancer activity while maintaining safety toward healthy cells. The use of xylooligosaccharides as a growth medium is innovative, as this plant fiber is known to promote beneficial bacteria growth and may enhance the production of therapeutic compounds.
This study has important limitations: it was conducted only in test tubes and cell cultures, not in living animals or people. The sample sizes for cell testing were not specified. The research doesn’t explain exactly which compounds in the fermented liquid are responsible for the anti-inflammatory and anticancer effects. It’s unknown whether these results would work in a living body, where the immune system, digestion, and other factors would affect the treatment. Cancer cells in a dish behave differently than tumors in a person. Much more research would be needed to determine if this could ever become a safe and effective human treatment.
The Bottom Line
This research is too early-stage to recommend for any medical use. It shows promise and warrants further investigation in animal studies and eventually human trials. People interested in probiotics should continue following their doctor’s advice and not self-treat cancer or inflammation with unproven bacterial products. The findings suggest xylooligosaccharides may be worth studying as a way to enhance beneficial bacteria, but more evidence is needed.
Researchers studying cancer treatments, inflammation, and probiotics should pay attention to these findings. People with breast cancer should not use this as a treatment—it’s far too early. People interested in natural health approaches may find this interesting as a direction for future research. Healthcare providers should be aware of this emerging research area but shouldn’t recommend it to patients yet.
If this research continues successfully, it would typically take 5-10 years of additional testing before any potential treatment could be considered for human use. Animal studies would come first, followed by safety testing in humans, then effectiveness testing. Even then, it might only become available as a supplement or complementary therapy, not a primary cancer treatment.
Frequently Asked Questions
Can I use this probiotic bacteria to treat cancer or inflammation?
Not yet. This 2026 research was conducted only in test tubes and cell cultures, not in living organisms or people. Much more testing would be needed before any potential treatment could be considered safe and effective for human use. Always consult your doctor for cancer or inflammation treatment.
What are xylooligosaccharides and should I eat them?
Xylooligosaccharides are plant fibers found naturally in foods like chicory root, onions, garlic, and asparagus. They’re generally recognized as safe and may support beneficial bacteria growth. However, this specific research doesn’t yet prove they provide the anticancer benefits shown in the lab study.
How long until this bacteria could become a cancer treatment?
If research continues successfully, it typically takes 5-10 years of additional testing before any potential treatment could be considered for human use. Animal studies would come first, followed by human safety and effectiveness trials. This is still very early-stage research.
Is Lactiplantibacillus plantarum already available as a probiotic supplement?
Some Lactobacillus plantarum strains are available as probiotics, but this specific strain (S61) and the xylooligosaccharide fermentation method are research-only at this time. Don’t assume commercial probiotics have the same properties shown in this laboratory study.
Why is this research important if it’s only in test tubes?
Early laboratory research helps identify promising compounds worth studying further. This study’s finding that the bacteria selectively killed cancer cells while sparing healthy cells is encouraging and suggests the research direction warrants animal and human studies. However, lab results don’t always translate to real-world effectiveness.
Want to Apply This Research?
- Users interested in probiotic research could track their daily probiotic intake and any inflammation symptoms (joint pain, digestive issues, energy levels) to monitor personal responses, though they should note this specific bacteria strain is not yet available as a consumer product
- Users could increase consumption of xylooligosaccharides (found in foods like chicory root, onions, and garlic) to support their existing beneficial bacteria, while staying informed about emerging probiotic research through the app’s research updates
- Set up a long-term tracker for inflammation markers (pain levels, swelling, digestive comfort) and general wellness, noting that this helps establish a personal baseline for discussing with healthcare providers as new treatments emerge
This research was conducted in laboratory test tubes and cell cultures only, not in living animals or people. The findings are preliminary and do not represent proven treatments for cancer or inflammation in humans. Do not use this information to self-treat cancer, inflammation, or any medical condition. Always consult with a qualified healthcare provider before starting any new treatment, supplement, or dietary change, especially if you have cancer or are taking medications. This article is for educational purposes only and should not be considered medical advice. Much additional research would be required before any potential treatment based on these findings could be considered safe and effective for human use.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.