Although there was no significant difference (P > 0.05) between the observation and control groups in systemic barrier function indicators such as DAO, D-lac, and LPS, the significantly higher CH4+H2 positivity may involve the following mechanisms: local barrier damage is prioritized over systemic alterations: colorectal polyps may mainly cause down-regulation of localized tight junction proteins in the mucosa (e.g., ZO-1) rather than widespread leaky gut. The gene discussed is TJP1; the disease is polyp of large intestine.