I have been told it is harmful because our fecal matter (poop) has alot of things in it that shouldn't sit in our intestines for very long because I've been told it put you a greater risk of cancer. Also you body has a mechanism called peristalsis which pushes food through your digestive system. If you hold off a bowel movement you WILL change this mechanism to work slower. How do I know this? Because this is how I am. Let's just say I had issues with BM's when I was a child so I would hold my BM. If you hold a BM you will become constipated and many people can't stand this. I have lived with it all my life and am quite used to it. I am tired a lot and have dry skin and think that this is the reason. Water is drawn to the bowels to help move waste out of the digestive system. I would recomend that everyone let there body do what it is supposed to do. Waste material needs to be discarded. Let me know if this helped you? iloveorange@earthlink.net

Aside from most people finding it very uncomfortable, yes, it is harmful. Between 40-60% by mass of what you poo out is not what you didn't use of your food, it is dead bacteria and the waste that the bacteria in your intestines produce. These are considered toxins, and keeping such toxins inside your body, in contact with the cells lining the bowel, for so long leads to cellular damage. By having such a long time between bowel movements, if you do this on a regular basis, you increase your chances of bowel cancer by 5-20x; although it can be difficult to determine what comes first sometimes -- constipation is also a frequent side effect of bowel cancer. Constipation can also be symptomatic of other problems, such as a poor diet or constant dehydration, which themselves will have knock-on effects on health. As well as it being linked with cancer, you can end up with benign bowel polyps which have to be removed surgically, or you can simply end up with an impacted bowel and hemorrhoids from straining. These are also not exactly desireable. Even worse is the fact that you can even end up with "fissures", the term for tears in the lining of the bowel, from the pressure of constipation, and this usually requires medical treatment. You increase your chances of colitis as well, where the bowel becomes inflamed and painful, and which feeds into the risk of cancer. A healthy diet and normal bowel operation should mean 1 or even 2 bowel movements a day.

Indeed so. Faecal matter contains toxins.The problem is more of an issue if one is a meat eater as meat is never properly digested and sits around in the digestive system for a long time.In three to five days the digestive system will be poisoned and if this is regular then bowel cancer is a real possibility. Also all the food you eat in those three to five days will back up behind the five day old bowel movement causing constipation. Straining to pass hard stool in those with a poor circulatory system can cause stroke in rare instances, but more commonly tearing of the anus.