Dysbiosis Concerns
Gut dysbiosis describes an imbalance in gut microbial communities associated with (but not proven to directly cause) various conditions, per the ACG clinician primer on the gut microbiome.
Symptoms
Dysbiosis itself has no defined symptom set -- it's a description of microbial imbalance, not a diagnosis; it's discussed in the context of conditions like C. difficile infection, inflammatory bowel disease, and IBS.
Causes and risk
Antibiotic use, diet, infection, and chronic disease can all shift gut microbial composition; there is no consensus definition of a "normal" microbiome, so there's no gold standard for what counts as dysbiosis.
How it is evaluated
Current evidence is conservative here: a 2025 international consensus statement concluded that no validated clinical test exists to guide or monitor microbiome-directed therapy, and that direct-to-consumer microbiome tests have outpaced the supporting evidence. Stool testing is also only a partial proxy for the whole gut microbiome, per NEJM review data.
Treatment
The American Gastroenterological Association recommends against probiotics for most GI conditions outside of a small number of evidence-based indications; fecal microbiota transplant has an established role specifically for recurrent C. difficile infection, per the ACG primer.
When to seek care
New diarrhea after a course of antibiotics should be tested for C. difficile. Bloody stools, fever, or signs of dehydration alongside GI symptoms warrant prompt evaluation.