GALT — gut-associated lymphoid tissue — is the largest immune organ in your dog's body, housing around 70% of their entire immune system within the intestinal wall. This network of Peyer's patches, M cells, and immune populations continuously monitors everything your dog swallows, deciding what to tolerate and what to fight. When GALT is disrupted, the consequences extend far beyond the gut — driving skin conditions, joint problems, and systemic immune dysfunction. Discover how GALT works and how targeted nutrition can support it.