Constipation occurs when there are fewer than three bowel movements per week. Chronic constipation is characterized by infrequent bowel movements or difficulty passing stools. Chronic constipation can interfere with some people's daily activities, even though occasional constipation is very common. People with chronic constipation may strain excessively to pass stools. The underlying cause of chronic constipation can be addressed in part to treat it. Some cases of diarrhea, however, do not have a clear cause. As a result of too much water absorbed from waste, the stool becomes hard in consistency and difficult to pass. As food passes through the digestive tract, nutrients are absorbed. Partially digested food (waste) is then transferred to the large intestine, commonly known as the colon. The colon absorbs water from these wastes and produces stool as a result. The digestive tract may move food too slowly if you are constipated. The colon has a hard time absorbing water from waste because it has too much time to absorb it. The stool becomes dry, hard, and difficult to pass as a result. Constipation can be caused by lifestyle choices, medical conditions, medications, or pregnancy.