Psyllium is a bulk-forming laxative. This means it soaks up water in your gut and makes bowel movements much easier and can help promote regularity without increasing flatulence. It can be used as a one-off to ease constipation, or it can be added to your diet to help promote regularity and overall digestive health. A healthy colony of good bacteria in the digestive system is essential for healthy immune function. Your body is better able to fight infection, reduce inflammation, and maintain healthy tissue and cells.