Constipation is a common complaint seen in many different patient populations. It occurs most commonly in the elderly, but even young patients can be constipated, especially if they are on chronic opiod therapy. The pathophysiology of this condition may be due to many factors. One potential cause is dehydration, causing hard stools. Another is neurological defects in the colon. Side effects from medication are yet another possibility for the slowing of faeces in transit through the large intestine.