Researchers tested whether probiotics (beneficial bacteria) could help reduce inflammation in people with endometriosis, a painful condition where tissue grows outside the uterus. In this study with rats, scientists found that probiotics changed the types of bacteria in the gut and increased helpful substances called short-chain fatty acids. These changes appeared to reduce inflammatory markers in the blood. While these results are promising, this was an animal study, so more research in humans is needed before we know if probiotics will have the same effect on people with endometriosis.

The Quick Take

  • What they studied: Whether giving probiotics (good bacteria) to animals with endometriosis could reduce inflammation and pain-causing chemicals in their bodies
  • Who participated: Eight laboratory rats divided into two groups: one eating normal food and one eating normal food plus probiotics. The study lasted four weeks.
  • Key finding: Rats that received probiotics had significantly lower levels of two inflammation-causing chemicals (TNF-α and IL-6) in their blood compared to rats eating regular food only
  • What it means for you: This suggests probiotics might help reduce inflammation related to endometriosis, but this was tested in rats, not humans. People with endometriosis should talk to their doctor before trying probiotics as a treatment, since we need human studies to confirm these findings work the same way in people

The Research Details

Scientists created endometriosis in laboratory rats to mimic the human condition. They then split the rats into two groups: one group ate regular food, while the other group ate the same food plus probiotics (beneficial bacteria). After four weeks, the researchers collected blood and stool samples from all the rats to measure inflammation markers and analyze the bacteria in their guts.

The team used several advanced techniques to understand what happened. They measured two key inflammation chemicals using a test called ELISA. They identified which bacteria were present in the gut using genetic sequencing (16S rRNA). They also measured nine different short-chain fatty acids—helpful substances that bacteria produce—using a technique called gas chromatography-mass spectrometry (GC-MS).

This type of study is called a controlled experiment because the researchers carefully controlled which rats got probiotics and which didn’t, allowing them to compare the results fairly.

This research approach matters because it helps scientists understand the connection between gut bacteria, inflammation, and endometriosis. By measuring multiple things (bacteria types, helpful substances they produce, and inflammation markers), the researchers could see the complete picture of how probiotics might work. This detailed approach provides clues for future human studies.

This study has some important limitations to consider: it was conducted in rats, not humans, so results may not apply the same way to people. The sample size was very small (only 8 rats total), which means the results are less reliable than larger studies. The study lasted only four weeks, which is relatively short. However, the study did use rigorous scientific methods and measured multiple related factors, which strengthens the findings within the animal model.

What the Results Show

The main finding was that probiotics significantly reduced two inflammation chemicals in the blood. TNF-α and IL-6 levels dropped substantially in the probiotic group compared to the control group (P < 0.01, which means there’s less than a 1% chance this happened by random chance).

The researchers also found that probiotics changed the types and amounts of bacteria living in the rats’ guts. The probiotic group had a different bacterial community structure that appeared more stable and balanced. This suggests probiotics work partly by reshaping which bacteria live in the digestive system.

Additionally, the probiotic group had higher levels of short-chain fatty acids in their stool. These are beneficial substances that bacteria produce when they break down fiber. Short-chain fatty acids are important because they help reduce inflammation throughout the body and support gut health.

The study identified a specific short-chain fatty acid called 4-MVA as a potential key player in how probiotics help reduce inflammation. While this finding is interesting, the researchers note it needs more testing before we can be sure it’s important. The researchers also found that probiotics improved the overall stability and balance of the bacterial community in the gut, which may contribute to the inflammation-reducing effects.

This research builds on growing evidence that gut bacteria play a role in endometriosis. Previous studies suggested that people with endometriosis often have different gut bacteria than people without the condition. This study adds to that knowledge by showing that changing the bacteria with probiotics might reduce inflammation. However, most previous research on this topic has also been in animals, so human studies are still needed to confirm these connections.

This study has several important limitations. First, it was conducted in rats, not humans, so we can’t assume the results will be identical in people. Second, only 8 rats were studied total, which is a very small number and makes the results less reliable. Third, the study only lasted 4 weeks, which is relatively short for understanding long-term effects. Fourth, the study didn’t test whether the rats actually experienced less pain or other endometriosis symptoms—it only measured inflammation chemicals and bacteria. Finally, the study didn’t compare probiotics to other treatments for endometriosis, so we don’t know if probiotics work better or worse than existing options.

The Bottom Line

Based on this animal study, probiotics appear promising for potentially reducing inflammation related to endometriosis (moderate confidence level). However, because this was only tested in rats, we cannot yet recommend probiotics as a treatment for people with endometriosis. Anyone with endometriosis interested in trying probiotics should discuss this with their doctor first. If you do try probiotics, look for products that contain the specific strains studied in research, and give them at least 4-8 weeks to see if they help.

People with endometriosis who are looking for ways to manage inflammation and pain should find this research interesting, though they should wait for human studies before making treatment decisions. Healthcare providers treating endometriosis may want to monitor this research area. People without endometriosis don’t need to change their behavior based on this single animal study. Pregnant women and people with weakened immune systems should consult their doctor before taking probiotics.

In this rat study, changes appeared after 4 weeks of probiotic use. If similar effects occur in humans, you might expect to see potential benefits within 4-8 weeks, though this is speculative. Some people report feeling better within 2-3 weeks, while others need 8-12 weeks. Individual responses vary significantly, so patience is important.

Want to Apply This Research?

  • Track daily probiotic intake (yes/no) and weekly pain levels on a scale of 1-10, along with digestive symptoms (bloating, gas, bowel regularity) to monitor personal response over 8-12 weeks
  • Users could set a daily reminder to take a probiotic supplement at the same time each day, and log their endometriosis symptoms weekly to see if they notice any patterns or improvements over time
  • Create a 12-week tracking dashboard showing probiotic consistency, pain trends, and digestive health changes. Include a feature to share results with healthcare providers to inform treatment decisions

This research was conducted in laboratory rats and has not been tested in humans. Endometriosis is a serious medical condition that requires professional medical care. Do not use this information to replace advice from your doctor. Before starting any probiotic supplement, especially if you have endometriosis, are pregnant, breastfeeding, or have a weakened immune system, consult with your healthcare provider. While probiotics are generally considered safe for most people, they can cause side effects in some individuals. This article summarizes one animal study and should not be considered definitive medical advice. More human research is needed before probiotics can be recommended as an endometriosis treatment.