www.AskTheDoctor-MS.com. Direct relationship between digestive system and nervous system. Digestive system is largest immune organ that is how we absorb nutrients and eliminate waste. A breakdown of the digestive lining allows toxins into the blood stream, carrying those toxins to the brain. This can disturb immune function in the brain. Complimentary medicine and supplements can help to decrease toxins in the gut, thereby decreasing toxins to the brain, which reduces the symptoms of MS. Visit www.AskTheDoctor-MS.com to learn more.