Fibre or Fiber in American English promotes good bowel function and improves general health. Eating at least 25 grammes of fibre a day is recommended, you get fibre only from plant foods and edible mushrooms. Eating plenty of fibre may cut the risk of diabetes, heart disease and obesity. Plants with high fibre content include fruit, grains (especially wholegrains), pulses, nuts, seeds vegetables. A healthy, varied diet should include different types of fibre.   
Eating fibre is a natural way to keep bowels regular. If you need anything some bran cereal, some prunes, dried or tinned apricots or other high fibre food you like is better for you than opening medicines you get at a pharmacy.