Lower GI endoscopy lets your doctor view your lower gastrointestinal (GI) tract. Your entire colon and rectum can be examined (colonoscopy). Or just the rectum and sigmoid colon can be examined (sigmoidoscopy).

Follow these and any other instructions you are given before your endoscopy. If you don't follow the instructions for getting ready for this test, the test may need to be canceled or done again. For this reason, read your instructions carefully before the exam. Call your doctor with any questions.

• Follow any directions you're given for not eating or drinking before the test. For a colonoscopy, you may be told to eat and drink only clear liquids for 1 to 3 days before the exam. You may have other diet changes.
• Take any laxatives that are prescribed for you. An enema may also be prescribed. Follow the instructions for these carefully.
• Arrange for someone to drive you home after the exam if you'll be sedated.
• Tell your doctor about all the medicines you take. This includes any prescription or over-the-counter medicines. It also includes vitamins, herbs, and other supplements. Also tell the doctor if you take any illegal drugs.
• Tell your doctor if you have any health problems or allergies.
• Discuss possible alternatives to the procedure, and risks, with your doctor.

• Colonoscopy can take 30 minutes or longer. Sigmoidoscopy often takes about 20 minutes or longer. The length of the procedure depends a lot on how clean your intestines are, the reason for the procedure, and what biopsies or treatments must be done.
• You lie on the stretcher or bed on your left side.
• For colonoscopy, you're given medicine to relax you (sedation) or to put you in a light sleep. This is given through an I.V. (intravenous) line. You can choose not to get any sedation medicines or to be put in a light sleep. Discuss this with your doctor. Sigmoidoscopy usually doesn't need sedation.
• The endoscope is a flexible tube with a light and camera at the end. It is inserted into your rectum. You may feel pressure and cramping. If you feel pain, tell your doctor. You may get more sedation, which includes pain medicine and an anti-anxiety medicine.
• The endoscope sends images of your colon to a video screen. Prints of the images may be taken as a record of your exam.
• Biopsies (tissue samples), polyp removal, or other treatments may be done.
• When the procedure is done, you rest for a time. You may have some discomfort right after the procedure from trapped air. This can be relieved by changing position and passing the air.
• If you've been sedated or put in a light sleep, you must have an adult drive you home. Don't work, drive, or make big decisions for 24 hours after sedation.

Contact your doctor if you have any of the following after the procedure:

• New or worse belly pain or cramps
• Fever of 100.4°F (38°C) or above, or as directed by your doctor
• Slight rectal bleeding
• Nausea or vomiting
• Stomach is hard and bloated.
• Lot of blood in your stools.

Call 911, or get immediate medical care at the nearest emergency department, if you:

• Feel faint, dizzy, or pass out (lose consciousness).
• Have chest pain or trouble breathing.
• Have heavy or prolonged rectal bleeding.