Common causes of constipation include: A low-fiber diet; GI problems, such as irritable bowel syndrome, obstructive tumors, and celiac disease; Travel and other changes to daily routines; Frequently using laxatives or enemas; Various medications. Whatever the cause, constipation is often associated with the same common signs and symptoms. Signs and Symptoms There's no real right number of bowel movements you should have in a day or week — it's different for each person.