Yeast in the gut refers to Candida, a type of yeast that naturally occurs in the intestines and other parts of the body. Candida is usually harmless, but when it grows too much, it can cause an infection called candidiasis. Candidiasis can affect the mouth, gut, and vagina. Some factors that can trigger an overgrowth of Candida include environmental changes, health issues, and antibiotics. ^{medicalnewstoday.com}+1 ^{1 2}