Colonoscopy vs. Endoscopy

The difference between a colonoscopy and an endoscopy

There are several tests that doctors can do to see inside body cavities. Two of these are colonoscopy and endoscopy. They each consist of a narrow tube with a light source on the end so that the doctor can see if there are any problems and be able to make a diagnosis. When it is used to see inside the upper abdomen and the large intestine it is called an endoscopy or an upper GI tract endoscope. A colonoscopy is the name given to the procedure used to see inside the colon.

Although the same device is used to see inside the lungs and to diagnose problems with the throat, there are different names for this procedure, such as bronchoscope for the lungs and laryngoscope for the throat. When it is used to see inside the uterus it is a hyteroscope and for viewing the inside of the abdomen in surgery, it is called a laparoscope.

The early endoscopes were metal tubes that were rigid and caused damage to the tissues. Also the visual scope was very narrow. The endoscopes used today make use of fibre-optic light and the tubing is flexible. The basic structure of the device consists of a camera at one end containing a source of light. There is also a biopsy needle included so that samples of tissue can be extracted and sent for testing.

In an endoscopy the doctor can see the food canal. The patient swallows the endoscope and in the process the doctor can see the wall of the esophagus, the stomach and the duodenum with the aid of the camera. This is the way in which peptic ulcers and cancers can be seen directly and tissue samples can be taken at the same time. In this way this procedure reduces the need for surgery. No preparation is necessary for endoscopy and the patient can return home after the procedure.

In a colonoscopy the doctor can see the large intestine. The colonoscope is inserted through the anus and because of this the patient will have to take medication for a few days in advance of the procedure to clear the fecal matter from the bowels. As with an endoscopy tissue samples may be taken or polyps removed. The patient will be able to return home once the procedure is complete.


  1. Endoscopy and colonoscopy are procedures in which the doctor can see the inside of the large intestine.
  2. An endoscope is inserted through the mouth and a colonoscope is inserted through the anus.
  3. Preparation is needed for a colonoscopy to clean the bowels.