Colonoscopy Preparation

20+ years of experience

5000+ scopes performed

Fellowship-trained colorectal surgeon

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What is a Colonoscopy?

A colonoscopy is a medical procedure that allows our doctor to carefully examine the inside of your large intestine (colon) and rectum. It is performed using a long, thin, flexible tube with a tiny camera at the tip, called a colonoscope.

This camera sends real-time images to a monitor, enabling the doctor to look for abnormalities such as polyps, inflammation, ulcers, or bleeding. Colonoscopy is considered the most accurate method for detecting and removing polyps, as well as identifying early signs of colorectal cancer before they cause serious symptoms.

Proper preparation is key, as a clean bowel ensures our doctor can see the colon lining and detect even small polyps during a colonoscopy.

Why would you need a Colonoscopy?

A colonoscopy is routinely recommended once you reach the age of 50. However, it may be advised earlier if you are at higher risk. The procedure may be recommended for specific individuals and scenarios. This includes:

Have symptoms such as rectal bleeding, changes in bowel habits, or unexplained abdominal pain
Have a personal or family history of colorectal cancer or polyps
Need follow-up after a previous polyp removal
Are above 50 years old and due for routine colorectal cancer screening
Require diagnosis or monitoring of conditions such as:
- Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis
- Diverticulosis or Diverticulitis
- Unexplained iron-deficiency anaemia
- Suspected colorectal tumours or strictures

How do I prepare for a Colonoscopy?

A low-fibre diet before colonoscopy helps reduce residue in the bowel, making it easier to fully cleanse and ensuring a clearer view during the procedure.

Preparation is crucial for a successful colonoscopy. A clean bowel allows our doctor to see the lining of your colon and detect any abnormalities, such as polyps, inflammation, or bleeding. Poor preparation may make the procedure less effective and could even mean it has to be repeated.

To reduce the likelihood of ineffective procedures, here is how you can prepare for it:

Dietary adjustments

Several days before – follow a low-fibre diet. Avoid foods that are harder to digest, such as whole grains, nuts, seeds, raw fruits and vegetables. Stick to foods that are soft and easy to digest.
One day before – switch to a clear liquid diet. This may include broth, clear juices without pulp, black coffee or tea (without milk), jelly, and ice pops.
Day of procedure – continue clear liquids only, until the cut-off time advises, usually a few hours before the colonoscopy .

Bowel preparation

Prescription laxatives – you will be prescribed a laxative solution designed to fully empty your bowels. Take it exactly as instructed, often split into 2 doses.
Timing – be prepared to spend several hours going back and forth to the toilet, as the solution will trigger frequent and sometimes urgent bowel movements.
Hydration – drink plenty of clear fluids to prevent dehydration during the process.
Follow instructions closely – incomplete preparation can obscure our doctor’s view of the colon, which may lead to rescheduling.

Other considerations

Medications – some medications, such as blood thinners or diabetes medicines, may need to be adjusted. Discuss this with our doctor beforehand.
Transportation – you will be sedated for the procedure, so arrange for someone to drive you home. Clinics typically will not allow you to leave alone.
Comfort – wear loose, comfortable clothing. Avoid applying lotion, powder, or oils on your chest and arms, as these can interfere with monitoring equipment.
Communication – if you are unsure about any instructions or if you encounter problems during preparation, feel free to drop us a call for guidance and our clinic staff will assist you.

If you are experiencing the symptoms,

consult a medical professional immediately.

Schedule an appointment with Dr Aaron Poh.

book an appointment

Timeline: A week before your Colonoscopy

For the procedure to be accurate and effective, your bowel needs to be thoroughly cleansed. This is why proper preparation is important. Here is a step-by-step guide on what to expect in the days leading up to your colonoscopy:

1 Week Before

Tell your doctor about all medications and supplements
Stop iron tablets (if advised)
Arrange for someone to accompany you
Eat lighter meals
Avoid tough meats, nuts, seeds and raw vegetables

2 to 3 Days Before

Switch to a low-fibre diet
Drink plenty of water
Focus on eating more white rice, plain bread, eggs, fish and chicken
Avoid wholegrains, beans, corn, fruit skin and seeds

1 Day Before

Clear liquid diet only, such as clear soups
Drink water, tea or coffee (without milk), apple juice or sports drinks
Avoid red, purple and blue liquids
Start bowel preparation as prescribed by the doctor

Day of Procedure

Finish the second dose of bowel preparations as instructed
No solid food
Only clear fluids until cut-off time (2 to 4 hours before procedure)
Take only essential medications with a sip of water
Arrive with your companion

Will I be conscious during a Colonoscopy?

Colonoscopy is a quick and straightforward procedure, usually completed within 30–45 minutes, with most patients going home the same day.

During a colonoscopy, most patients are given medication to keep them comfortable. You generally will not feel pain, and in most cases, you will not even remember the procedure. There are two main options:

Moderate sedation – you will receive medication through an IV line that makes you drowsy and relaxed. You will fall into a moderate sleep with no memory of the procedure.
General anaesthesia – you will be completely asleep throughout the colonoscopy. This option is less common and usually recommended when the colonoscopy is performed in tandem with other surgical procedures or or in certain medical situations.

Dr Aaron Poh will review your health, comfort needs, and risks before deciding which form of sedation or anaesthesia is most suitable for you.

What are some of the common side effects of a Colonoscopy?

It is normal to experience some temporary effects after a colonoscopy, especially as your body recovers from the bowel preparation, sedation, and the procedure itself. These side effects are usually mild, not a cause for concern, and tend to resolve within a day.

Some of the more common ones include:

Bloating or cramping – this happens because air is introduced into the colon during the procedure to expand the bowel for better visibility. Passing gas often relieves discomfort.
Drowsiness or grogginess – the sedative medications can make you feel sleepy or unsteady for the rest of the day. That is why driving or operating machinery is not allowed until the effects fully wear off.
Mild rectal bleeding – a small amount of blood may appear if a biopsy was taken or a polyp was removed. This usually stops quickly.
Nausea – some patients may feel slightly nauseated due to sedation or the bowel prep solution, but this is generally temporary.
Sore throat (rare) – if the procedure involved additional scopes or airway support during anaesthesia, you may have minor throat irritation.

If you develop severe abdominal pain, heavy bleeding, fever, or persistent dizziness, you should contact our doctor immediately, as these may be signs of a complication, though they are very rare.

Schedule Your Appointment with Dr Aaron Poh.

Summary

A colonoscopy is one of the most reliable tools for diagnosing and preventing colorectal cancer. Detecting and removing polyps early significantly lowers your risk of developing serious disease. While the preparation process may feel inconvenient, it is essential for ensuring our doctor has a clear view of your colon. The procedure itself is safe, usually painless thanks to sedation, and recovery is quick for most patients. With proper preparation and follow-up, a colonoscopy offers peace of mind and can even be lifesaving.

Frequently Asked Questions (FAQs)

Why is bowel preparation so important?

A clean bowel allows our doctor to see the lining of your colon. If the bowel is not properly cleaned, small polyps or abnormalities may be missed, and in some cases, the procedure may need to be repeated.

What drinks are considered clear liquids?

Clear broth, apple juice, white grape juice, plain tea or coffee (without milk or cream), clear soft drinks, sports drinks, jelly (not red or purple), and water.

What if I cannot finish the bowel prep solution?

Try drinking it in smaller amounts over time or chill it to improve the taste. If you struggle, contact your clinic for advice. It’s important to finish as much as possible for the colonoscopy to be effective.

Can I take my usual medications before a colonoscopy?

Some medicines, such as blood thinners, diabetes medications, or iron tablets, may need to be adjusted or paused. Always check with our doctor well in advance.

Can I continue to drink water on the day of the procedure?

Yes, but you must stop all liquids a few hours before your scheduled procedure.

Do I need to stop alcohol or smoke before the procedure?

Yes. Alcohol and smoking can interfere with sedation and hydration. Avoid both for at least 24 hours before.

How do I manage work or daily life during prep?

You will need frequent access to a restroom after starting the laxative solution, so plan to stay at home. Wearing loose clothing and applying soothing cream to the anal area may also help with comfort.

Can I drive myself to the appointment?

No. Sedation will affect your alertness and ability to focus. You are advised to arrange for someone to drive you home after the procedure.

Is a colonoscopy procedure painful?

No, the procedure is performed under sedation, so you will not feel any pain.

Can I work or exercise while preparing for a colonoscopy?

It is best to rest while preparing for your procedure, as the bowel preparation medicine will cause frequent trips to the toilet. Light activities at home are fine, but avoid doing strenuous activities until after your procedure.

Meet Our Doctor

DR AARON POH

Dr Aaron Poh is a fully accredited General Surgeon with dual subspecialties in Colorectal Surgery and Trauma Surgery, recognised by Singapore’s Specialist Accreditation Board and Ministry of Health. He is the Medical Director of Alpine Surgical Practice, with clinics located at Mount Elizabeth Hospital, Parkway East Hospital, and Farrer Park Hospitals.

Dr Aaron Poh has extensive experience, having performed over 5,000 endoscopic procedures. He is a strong advocate for early detection through colonoscopy, particularly for individuals at risk of colorectal cancer. His expertise includes advanced endoscopic techniques such as Endoscopic Mucosal Resection (EMR) for complex polyps and colonic stenting for obstructed cancers, which help patients avoid major emergency surgery.

When surgery is required, he specialises in minimally invasive laparoscopic colorectal cancer surgery, offering patients faster recovery with less pain and scarring. In addition to cancer care, he manages a wide range of anal conditions including haemorrhoids, fistulas, fissures, and abscesses, providing comprehensive colorectal treatment.