The lining of your intestines is an essential wall with microscopic holes in it that allows vitamins, minerals, and nutrients from the food into the bloodstream while at the same time trying to keep the bad bacteria, undigested food in the stomach, and other toxic waste from getting out. When the balance of gut bacteria is right, your whole body system could function well yet the gut bacteria is imbalanced due to stress, severe constipation, exposure to environmental toxins like pesticides, eating a poor diet, or taking an antibiotic. The “bad” bacteria form holes in the gut wall and some of the bacteria move along with food particles and toxins which leak into the bloodstream. Therefore, your immune system are weak, it is then attacked by these “bad” bacteria that lead irritation and inflammation.

Source from:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6790068/