The term constipation actually means to have incomplete, infrequent or difficult bowel movements. It can also mean a feeling of not completely emptying the bowel after a bowel movement. Your number of bowel movements does decrease with age though. Going without one for three or four days can cause physical and mental distress for some. In addition, even though you hear about "toxins" staying in the bowel and causing all sorts of trouble on TV this is simply not true.
Constipation can be chronic or acute. Acute constipation can be the cause or a symptom of some serious medical illnesses. If it is accompanied by nausea, vomiting, abdominal pain, rectal bleeding or weight loss, it is important to consult a medical practitioner.
There are also some medications that frequently cause constipation in the people who take them. These include narcotic pain medications, antidepressants, anticonvulsants, iron supplements, aluminum containing antacids and calcium channel blocking drugs.
Your habits can also influence your constipation. Whether or not we realize it our bowel movements are under voluntary control. Suppressing this urge too frequently can lead to constipation because the urges disappear.
Fiber is especially important in maintaining a healthy bowel regime. Try to get at least 20 grams a day. The best place to get this from is fresh fruits, vegetables and whole grains.
Surprisingly, Laxatives can be a cause of constipation also. Using stimulant laxatives over a long time causes damage to the nerves and muscles of the colon and this can cause constipation. Only use these as a last resort to treat your constipation.
Treatments for constipation besides increasing our fiber can also include laxatives (again, stay away from stimulant ones unless directed by your doctor). There are lubricant laxatives that contain mineral oil or a combination of water and the oil. Emollient laxatives (also known as stool softeners), and hyperosmolar laxatives which are indigestible and remain in the colon to retain water and cause a bowel movement, and saline laxatives which cause water to be drawn into the bowel and soften the stool.
There are also enemas and suppositories. Enemas come in several types but they work on the same principal. They stimulate the bowel by distending the rectum. Suppositories come in medicated and glycerin types. The glycerin type irritates the rectum to cause the bowel movement and the medicated ones also stimulate the rectum to achieve the same effect.
If you are constipated try increasing your fiber first and if that doesn't work ask your doctor for advice.