On short, the colonoscopy procedure is the examination of the lining of the colon or large bowel using a tube telescope.
Ussualy, colonoscopy is done as a result of abdomen pain.
The procedure doesn't last too long(20-50 min) and you are not required to stay in hospital overnight.

The procedure itself requires the colon to be completly empty for a clear view, so a special diet is required for a few days before. Drinking a lot of water a day before is essential.

There are a few reasons why someone should follow this procedure.
Altough colonoscopy is usually followed by old aged people(50 years), some may need to do it earlier.
With the help of colonoscopy, polyps, cancer or other related diseases can be discovered and I consider this to be a main benefit.

After effects of a colonoscopy, also called side-effects are the unwanted but they are temporary.
Here are a few of them:
- feeling bloated - lasts a very short period of time so you don't have to worry. Moving around can help eliminate abdominal bloating.
- feeling sleepy - a sedative result
- if a biopsy was made during procedure, blood may be present in the stool
Some people may experience abdominal pain or fever.

Complications are very rare, and most people are not affected, but you should be aware of them. These include risks of colon perforation, which can raise infections and bleeding.
Also, there are cases of not successfully completed colonoscopy and may need to be repeated.

There are two main colon diseases that can be discovered with this procedure : Ulcerative Colitis and Colorectal Cancer

Altough it is beyond of the scope of this article, I decided to offer a few basic information on them.

Ulcerative colitis - it is a chronic disease of unknown cause defined by severely inflamed lining and rectum, forming shallow sores known as ulcers. In most cases, the colon is permanently damaged. Symptomps include rectal bleeding and diarrhea. Ulcerative colitis patients present the risk of colon cancer.

Colorectal Cancer - malignancy of the large intestine. Colorectal cancer is the third most common cancer among Americans, but new techniques can detect this in it's early stages and 80-90 % can be cured in this cases.
Research has shown that certain foods can increase risk of colorectal cancer, mainly red meat and animal fat. Diets high in fiber(fruits and vegetables) can reduce the risk. Primary treatment is surgery.

Annals of Internal Medicine published a recent study : colonoscopy screening prevents two thirds of deaths due to colorectal cancer on the left side of the colon, but not the right part.