Constipation is a common problem which can be caused by a number of things. Not eating enough fibre or not drinking enough fluid can cause constipation. Some conditions (such as pregnancy) can cause constipation, as can a lack of exercise or movement (such as being ill in bed) and some medicines.
This is a companion discussion topic for the original article at https://patient.info/medicine/ispaghula-husk-for-constipation-fybogel-ispagel-yourfibre