Dietary fiber is the indigestible portion of food derived from plants, fruits or grains. There are two different components, soluble and insoluble fiber one which solves in water, often found in fruits and vegetables. The other does not solve in water, often found in grains. Both fibers are important for healthy digestion a regular and easy bowl movement as well as a softer stool.
For the purpose of curing hemorrhoids adding dietary fiber is used to
1. regulate the frequency of the bowl movement
2. keeping the stool soft and moist, avoiding to much straining.