Why Laxatives Fail: Bacteria May Be Drying Out Your Colon
Researchers in Japan have uncovered a surprising cause of long-lasting constipation. Instead of slow bowel movement alone, they found a pair of gut bacteria that actively strip away the colon’s natural mucus layer. This process leaves stool dry and hard to pass.
The discovery, led by scientists at Nagoya University, introduces a new medical concept now being called bacterial constipation and may explain why standard laxatives fail for many people.
Importantly, the findings also shed light on severe constipation seen years before movement symptoms appear in Parkinson’s disease.
Two bacteria work together to dry out the gut
The research team discovered that two common gut microbes act in sequence:
- Bacteroides thetaiotaomicron goes first. It removes sulfate shields from intestinal mucus.
- Akkermansia muciniphila follows, feeding on the now-exposed mucus.
Under normal conditions, sulfate groups protect colonic mucin, a gel-like coating that lines the large intestine. This mucus keeps stool moist, helps it move smoothly, and forms a barrier against harmful microbes.
However, when these bacteria become too active, they destroy large amounts of mucin. As a result, the stool loses water, becomes stiff, and struggles to move forward. That is when bacterial constipation begins.
Because the problem comes from mucus loss rather than slow gut muscles, many people do not respond well to typical constipation medicines.
Why does this matter for everyday patients
Constipation affects millions worldwide. Doctors often blame weak bowel movement, yet many patients have no clear cause. This group is usually diagnosed with chronic idiopathic constipation.
People with Parkinson’s disease face an even tougher challenge. Many live with serious, treatment-resistant constipation for 20 to 30 years before tremors or stiffness appear. Until now, experts mostly blamed nerve damage.
This study suggests something else plays a major role: gut bacteria that dry out the colon from the inside.
Blocking one enzyme stopped constipation in mice
To confirm their theory, the team altered Bacteroides thetaiotaomicron so it could no longer produce sulfatase, the enzyme that removes sulfate protection from mucus.
Led by Tomonari Hamaguchi, the researchers placed these modified bacteria into germ-free mice along with Akkermansia muciniphila.
The result surprised them.
The mice did not become constipated. Their intestinal mucus stayed intact, and stool remained moist.
This experiment proved one key point: if doctors can block sulfatase, they may prevent bacterial constipation at its source.
A new direction for gut health treatment
Instead of relying only on laxatives or drugs that stimulate bowel movement, future therapies could target the bacteria themselves or the enzymes they use.
Such treatments may bring relief to people who have struggled for years, including those living with Parkinson’s disease.
By addressing the microbial cause directly, doctors may finally help patients whose constipation never improved with standard care.
Conclusion
The researchers now hope to develop medicines that safely inhibit sulfatase activity in humans. If successful, this approach could open an entirely new chapter in digestive care.
For patients frustrated by chronic symptoms, bacterial constipation offers both an explanation and new hope.
As scientists continue to explore the gut microbiome, this discovery reminds us that tiny organisms can have a huge impact on everyday health and quality of life.
Source:Â Inputs from various media SourcesÂ
I’m a pharmacist with a strong background in health sciences. I hold a BSc from Delhi University and a pharmacy degree from PDM University. I write articles and daily health news while interviewing doctors to bring you the latest insights. In my free time, you’ll find me at the gym or lost in a sci-fi novel.
- Health News and Updates,People Forum
- 20 February 2026
- 11:00
