Psyllium is a soluble fiber derived from the seeds of Plantago ovata, commonly used as a bulk-forming laxative. Its primary clinical use is for the treatment of constipation and, to a lesser extent, to help modulate blood sugar and cholesterol levels. The concept of "Leaky Gut Syndrome" refers to increased intestinal permeability, which is thought (though not universally accepted in mainstream medicine) to contribute to various gastrointestinal and systemic disorders.

There is some preliminary scientific evidence suggesting that psyllium may improve gut barrier function. Studies in animals and small human trials have indicated that psyllium supplementation can enhance the production of short-chain fatty acids, particularly butyrate, which helps support the integrity of the gut lining. Some research also points to psyllium's ability to modulate gut microbiota and reduce markers of inflammation, which could theoretically benefit intestinal permeability. However, clinical trials directly investigating psyllium's effects on "leaky gut" in humans are limited, and results are mixed or indirect.

In summary, while there is a plausible scientific rationale and some supportive mechanistic data, robust clinical evidence for psyllium’s use in treating or supporting "Leaky Gut Syndrome" specifically is lacking, and the condition itself remains somewhat controversial in conventional medicine. Psyllium is not traditionally used for this purpose, and its application is based on emerging, but not definitive, scientific findings.