Constipation will affect most people at some point during their lives and affects between 17% and 20% of healthy individuals at any one time. It affects people of all ages and both genders. Almost anyone can become constipated. However, some people are more likely than others to experience constipation: including older people, pregnant women, travelers, people taking certain medications or for those who may have had surgery.

In reality, constipation has relatively little to do with how many times you've had a bowel movement. It's normal for someone to have anywhere from 3 bowel movements per week to 3 bowel movements a day. If your stools are soft and pass easily and you pass them at least 3 times per week, you're not constipated.

To understand constipation, it helps to know how the colon (large intestine) works. As food moves through it, the colon absorbs water while forming waste products, or stool. Muscle contractions in the colon push the stool toward the rectum. By the time stool reaches the rectum, it is solid because most of the water has been absorbed.

Sometimes, constipation may be a side effect of a medicine that you are taking. Some of the most common types of medication which can cause constipation include:

- aluminium antacids (medicine to treat indigestion),
- antidepressants,
- antiepileptics (medicine to treat epilepsy)

Occasional constipation is the most common type of constipation. Almost anyone can experience occasional constipation. Some people are more likely than others to experience this type of constipation. These include the elderly, pregnant women, travelers, people taking certain medications or for those who may have had surgery. This type of constipation can be easily treated with changes in lifestyle and occasional use of laxatives

Acute constipation is constipation that is temporary, occurs suddenly and is usually a reaction to a particular cause. It can re-occur from time to time.

Hypotonic constipation or atonic constipation. "Hypotonic" means decrease in abdominal muscle tone. Weak abdominal muscles are not able to push the bowel to move as much as they should . The sufferer is characteristically bloated. This kind of constipation is caused by sedentary lifestyle, insufficient peristalsis, dietary fiber and fluid intake.

Functional constipation is defined to have no physical, hormonal or other body chemistry cause. It may have a neurological, psychological or psychosomatic cause. It happens due to poor diet and lifestyle.

Rectal constipation. When a person is too busy or distracted to be aware of nature's call to evacuate, he is training his rectum to be unresponsive. Eventually, the rectum will not send signals to the brain even when it is full. Dried fecal material becomes lodged and difficult to move.

Sometimes, people think they're constipated when in fact they are not. It is not necessary to move your bowels every day and some perfectly healthy people only move their bowels three times a week.