【Major points】

1. Follow a clear liquid diet the day before the colonoscopy. 
2. You cannot eat any food, drink water, or take medication for at least four hours before the painless colonoscopy.
3. After the colonoscopy, you may feel mild abdominal distension. You can walk around to promote bowel movement and reduce the discomfort.

Colonoscopy is to insert an endoscopy from anus to cecum and to directly observe the large intestine and rectal mucosa. Tumor lesions or polyps discovered during a colonoscopy will be excised or a biopsy will be performed to achieve the purposes of diagnosis and treatment. 

Pre-colonoscopy preparations:

1. The physician will explain the purpose and process of the colonoscopy, and ask you to fill in the informed consent form for colonoscopy and treatment.
2. Follow a low-fiber diet two days before the colonoscopy, such as white toast, porridge, white noodles, cellophane noodles, minced pork floss or minced meat, etc. Avoid eating stalked vegetables (cauliflower, water spinach, celery), seed-containing fruits (guava, kiwi, Dragon fruit), grains and nuts, and dairy products (milk, goat's milk, cheese, yogurt).
3.  Follow a clear liquid diet the day before the colonoscopy, such as sports drinks, rice soup, chicken essence, clear soup, tea, honey water, slag-free fruit juice (apple juice, wax guard tea), etc.; do not drink soy milk, milk, Ensure, or other fiber-containing food.
4. After noon on the day before the colonoscopy, start taking a laxative according to the physician's instructions. According to the type of laxative, it is necessary to take the laxative with more than 2000 CC of water.
5.  If the stool is not completely cleared after drinking the laxative, take the laxative again according to the physician’s orders. The colonoscopy cannot be accurate unless there is clean bowel preparation.
6.  On the day of the colonoscopy, patients who will receive general colonoscopy can still take clear liquid diet. Those who will receive painless colonoscopy cannot eat any food, drink water, or take medicine for at least four hours before the procedure.
7. Patients may keep taking blood pressure lowering drugs and heart medications as usual. However, for diabetes patients, blood sugar lowering drugs should be suspended on the day of colonoscopy. After colonoscopy is completed, diabetes patients may take blood sugar lowering drug again after a meal. 

1.  During the examination, the body faces to the left and the knees are bent towards the stomach in a shrimp-like posture.
2. After the endoscope is inserted into the anus, a small amount of air will be injected to assist the doctor in locating the intestinal cavity.
3. When the endoscope reaches the sigmoid colon, the medical staff will assist you to change the posture to a supine position so that the endoscope can pass through the right colonic flexure.
4. This examination does not require anesthesia. If the patient is tense or the examination is difficult due to intestinal stickiness, excessive curvature of the intestinal tract, sedatives and analgesics can be injected at their own expense to reduce discomfort. At this time, family members must be accompanied.
5. If you feel any discomfort during the examination, please take the initiative to express it to the medical examiners on site.

Principles of Post-colonoscopy care:

1. The nurse will pay attention to the changes in your blood pressure, pulse, breathing, and body temperature.
2. After the colonoscopy, you may experience mild abdominal distension and abdominal discomfort. You can turn over and move more to help pass gas and reduce the discomfort. If you experience severe abdominal pain or bleeding, please inform the healthcare personnel immediately.
3. After the colonoscopy, on the same day, you can resume your normal diet. If you underwent a biopsy or polypectomy during the colonoscopy, follow a low-fiber or clear liquid diet as instructed by your physician. Gradually increase your fiber intake the next day. Avoid eating fried and spicy foods because irritation of the intestines.
4. You cannot drive after the colonoscopy if you receive a painless colonoscopy or have sedatives and analgesics during the examination.
    

References

1. Lin, H. C, & Yeh, C. (2019). Colonoscopic perforations: A single center experience with 10 years in Taiwan. The Journal of Society of Colon and Rectal Surgeons (Taiwan), 30 (1), 28-35. https://doi.org/10.6312/scrstw.201903_30(1).10725
2. Tontini , GE, Prada, A., Sferrazza, S., Ciprandi , G., & Vecchi , M. (2021). The unmet needs for identifying the ideal bowl preparation. JGH O pen, 5 (10), 1135-1141 . https://doi.org/10.1002/jgh3.12653
3. Wu, Z.H., Li, Y.L., Li, Y.H. & Fang, G.J. (2022). Bowel preparation before colonoscopy . Monthly Journal of Clinical Medicine, 89 (3), 183-192. https://doi.org/10.6666/ClinMed.202203_89(3).0032
4. Zheng, J.L., Lin, H.T., Cui, Y.N, Zhong, Y.W., Li, B.P., & Guo, Y.L. (2022). The quality index and latest progress of colonoscopy examination. Taiwan Medical Journal, 65 (6), 24-34.