Home
Articles
Q&A

Why is it necessary to take laxatives before a colonoscopy?

Mar 21, 2025 Source: Cainiu Health
Dr. Shen Yonghua
Introduction
In general, the reasons for taking laxatives before a colonoscopy include cleansing the bowel, improving diagnostic accuracy, reducing procedural difficulty, minimizing the risk of complications, and following examination requirements. The primary function of laxatives is to clear solid fecal matter, secretions, and undigested food from the intestine, allowing the physician to clearly visualize the intestinal mucosa and identify any pathological changes during the colonoscopy.

Generally, there are several reasons why laxatives must be taken before a colonoscopy, including cleansing the bowel, improving diagnostic accuracy, reducing the difficulty of the procedure, minimizing the risk of complications, and meeting procedural requirements. Details are as follows:

1. Bowel Cleansing: The primary function of laxatives is to clear solid fecal matter, secretions, and undigested food from the intestine. This allows the physician to clearly visualize the intestinal mucosa during the colonoscopy and detect abnormalities such as congestion, edema, and erosion. This is the primary reason for taking laxatives before a colonoscopy.

2. Improve Diagnostic Accuracy: A large amount of fecal matter within the intestine can significantly compromise the accuracy and safety of a colonoscopy, potentially leading to missed or incorrect diagnoses. Therefore, bowel cleansing with laxatives enhances the accuracy of colonoscopy.

3. Reduce Procedural Difficulty: Residual materials in the intestine not only impair the physician's visibility but also make it difficult to advance the colonoscope. After cleansing the bowel, the colonoscope can be inserted more easily, thereby reducing the difficulty of the procedure.

4. Minimize Risk of Complications: Inadequate bowel preparation may increase the difficulty and duration of colonoscopy, and could even increase the risk of complications such as bleeding or perforation. Taking laxatives helps reduce these risks.

5. Follow Procedural Requirements: Strict bowel preparation is required before colonoscopy, as it is an essential prerequisite for a successful examination. Taking laxatives is an important step in bowel preparation, and patients should follow medical advice regarding proper administration.

Patients should take laxatives as directed by their physician and cooperate with other bowel preparation procedures to ensure smooth execution of the colonoscopy and accurate results.

References:

[1] Chen Xiao-ping, Wang Jian-ping, Zhao Ji-zong. Surgery (9th Edition) [M]. Beijing: People's Medical Publishing House, 2018.

[2] Chinese Society of Digestive Endoscopy, Chinese Medical Association. Chinese Guidelines for Bowel Preparation Related to Digestive Endoscopic Diagnosis and Treatment (2021 Edition) [J]. Chinese Journal of Digestive Endoscopy, 2021.

Related Articles

View All
What are the efficacy and side effects of phenolphthalein tablets?
The functions of phenolphthalein tablets include treating constipation, cleansing the intestines and removing toxins, promoting digestion, relieving intestinal gas accumulation, preparing for colonoscopy, etc. Side effects include intestinal dysfunction, electrolyte imbalance, allergic reactions, intestinal melanosis, induced arrhythmia, etc. It is recommended to take the medication as directed by a physician. When experiencing constipation, do not blindly self-administer phenolphthalein tablets; instead, first attempt to improve the condition by adjusting dietary habits and other methods.
avatar
Dr. Bai Hongmei
View Full Answer
Is it generally the case that a biopsy during a colonoscopy is not a good sign?
In general, obtaining a biopsy during a colonoscopy does not necessarily indicate a serious condition. It is a routine clinical method used to clarify the nature of lesions, and there is no need for excessive anxiety. Performing a pathological examination during colonoscopy does not always imply a severe problem; rather, it is primarily a diagnostic tool used to determine the condition of the intestine and guide subsequent treatment and management.
avatar
Dr. Shen Yonghua
View Full Answer
What should I do if I feel nauseous and cannot drink the electrolyte solution before a colonoscopy?
During a colonoscopy preparation, if you find it difficult to drink the electrolyte solution and feel nauseous, this can generally be alleviated by drinking small amounts frequently, consuming it after refrigeration, taking it with bland food, slowing down the drinking speed, or adjusting the drinking temperature. The effectiveness of these methods may vary among individuals. While drinking the electrolyte solution, it is important to stay relaxed and avoid excessive anxiety, which could worsen the discomfort. If you are still unable to tolerate the solution after trying the above measures,
avatar
Dr. Shen Yonghua
View Full Answer
How long should one fast before a physical examination?
Physical examination requires fasting for 8 to 12 hours in advance. If the examination includes gastroscopy or colonoscopy, a longer fasting period may be needed, and it is recommended to stop eating 10 to 12 hours beforehand. These types of examinations require a high level of intestinal cleanliness, and an extended fasting period ensures complete emptying of food from the gastrointestinal tract, avoiding interference from food residue with the visual field during the examination and improving the accuracy of results.
avatar
Dr. Yang Ziqi
View Full Answer
How to Determine if It's Hemorrhoids or a Polyp
Hemorrhoids and polyps can generally be differentiated based on symptoms, characteristics of the mass, features of rectal bleeding, digital rectal examination, and colonoscopy. Hemorrhoids commonly present with anal heaviness, itching, and severe pain when internal hemorrhoids prolapse and become incarcerated; polyps often have no obvious symptoms, although some may experience abdominal pain, diarrhea, or changes in bowel habits. If any abnormalities are noticed, prompt medical consultation is recommended.
avatar
Dr. Li Jingxiang
View Full Answer
Can I have a colonoscopy if I have hemorrhoids?
If hemorrhoid symptoms are mild, without significant swelling, bleeding, or prolapse of the hemorrhoidal mass, undergoing a colonoscopy generally does not cause serious adverse effects. During the colonoscopy, the physician will perform the procedure gently to minimize irritation to the anal area. Additionally, adequate lubrication will be applied beforehand to reduce friction. Under these circumstances, patients typically tolerate the examination well, and hemorrhoid symptoms are unlikely to worsen significantly.
avatar
Dr. Li Jingxiang
View Full Answer
How to Determine if It's Rectal Bleeding or Hemorrhoids
Determining whether the bleeding is from the rectum or hemorrhoids generally involves analysis of the bleeding site, blood color, accompanying symptoms, digital rectal examination, and colonoscopy. Hemorrhoidal bleeding typically originates from the hemorrhoidal venous plexus near the dentate line of the anal canal, with the bleeding site located close to the anus. Rectal bleeding arises from the rectal mucosa or blood vessels in the upper part of the intestinal tract, which is relatively farther from the anus.
avatar
Dr. Li Jingxiang
View Full Answer
Can I have a colonoscopy if I have hemorrhoids?
If hemorrhoid symptoms are mild, without significant bleeding, swelling, or prolapse of hemorrhoidal tissue, a colonoscopy examination is generally not significantly affected. During the colonoscopy, the physician will perform the procedure gently according to the specific situation. Additionally, proper bowel preparation before the examination and standardized procedures during the exam typically do not exacerbate hemorrhoid symptoms. Patients in such circumstances may undergo the examination after evaluation by a physician.
avatar
Dr. Li Jingxiang
View Full Answer
彩牛养生

Your trusted source for health information and wellness guidance.

Quick Links

Resources

Connect

© 2024 HealthPortal. All rights reserved.