How to Prepare for Your Colonoscopy: Step-by-step Guide by …

Health & Wellness Dr. Shekhar Poudel, Gastroenterologist & Hepatologist • April 19, 2026 • 4 min read

Learn how to prepare for a colonoscopy with Dr. Shekhar Poudel at the National Gastro Liver Center. Expert step-by-step bowel prep guide for patients in Lalitpur and Kathmandu, Nepal.

Expert Lead: Dr. Shekhar Poudel – Gastroenterologist & Liver Specialist in Nepal.

A successful colonoscopy depends entirely on the quality of your bowel preparation. If your colon is not completely clear, your doctor may miss important details like polyps or inflammation. This guide provides the official preparation protocol used at the National Gastro Liver Center in Lalitpur,Kathmandu.

Click here to watch full video guide by Dr. Shekhar Poudel ....

Dr. Shekhar Poudel explaining colonoscopy preparation at National Gastro Liver Center.

What is a Colonoscopy?
Diet Plan prior to colonoscopy
How to Take Bowel Preparation Medication
Day of Procedure Protocol
Frequently Asked Questions

A. What is a Colonoscopy and Why is it Necessary?

A colonoscopy is a safe medical procedure used to examine the inner lining of the large intestine (colon) and rectum. It is the gold standard for detecting:

Colorectal Cancer: Early detection of tumors.
Polyps: Removing small growths before they become cancerous.
Chronic Symptoms: Investigating persistent abdominal pain, chronic diarrhea, constipation, or blood in stool.

Learn more about our specialized Digestive, Liver Health and Diagnostic Services in Nepal.

B. 24 Hours Before: The Diet and Initial Preparation

To ensure the bowel cleansing medication works effectively, you must adjust your diet one day before your appointment at out Lalitpur clinic.

What to Eat (and Avoid)

Avoid: Green leafy vegetables
Legumes (beans)
Oily or fried foods
Dairy products (milk/ghee).
Focus on: Clear liquids
Plain white rice
Lght broths.

Evening Medication (6:00 PM – 7:00 PM)

Bisacodyl: Take two tablets as prescribed.
Lactulose: Take 30ml of the solution. These initial doses begin the cleansing process by stimulating bowel movements.

Colonoscopy bowel preparation kit featuring Bisacodyl tablets and Lactulose solution at National Gastro Liver Center

C. Day of Procedure: The "Cleanse" Protocol Book Appointment

On the morning of your procedure, you must remain on a clear liquid diet (black tea, lemon water, or oral rehydration salts like Jeevan Jal).

How to Take the Bowel Preparation Medications (Peglec / Polylec)

The most critical part of your preparation is the Polyethylene Glycol (PEG) solution.

1. Mix: Dissolve one full packet of PEG (Peglec or Polylec) into 2 liters of water.

2. Timing: Begin drinking this 5 hours before your scheduled appointment.

Example: If your appointment is at 9:00 AM, start drinking at 4:00 AM.

3. Pace: Drink the entire 2 liters slowly over 3 to 4 hours.

Example of clear, yellowish liquid stool indicating successful bowel preparation for colonoscopy at National Gastro Liver Center.

Important Note: You can stop drinking the solution once your bowel movements are clear and watery (resembling urine). However, finishing the prescribed dose is recommended for the best results by Dr. Shekhar Poudel

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Find us at the National Gastro Liver Center in Lalitpur: (Link to Google Maps)

References:

American Society for Gastrointestinal Endoscopy (ASGE): Bowel Preparation Guidelines for Colonoscopy
Mayo Clinic: Colonoscopy Preparation: What to expect

About the Expert

Dr. Shekhar Poudel, Consultant Gastroenterologist and Liver Specialist at National Gastro Liver Center, Lalitpur, Nepal.

Dr. Shekhar Poudel is a Consultant Gastroenterologist at the National Gastro Liver Center in Lalitpur. He specializes in advanced digestive and liver care, providing international-standard hygiene and clinical excellence for patients across Kathmandu and Nepal.

Frequently Asked Questions

A medical procedure using a flexible camera (colonoscope) to examine the lining of the large intestine and rectum.

It is used to screen for colon cancer, remove polyps, and investigate symptoms like chronic diarrhea or blood in stool.

When performed by experienced specialists at NGLC, the procedure is safe and efficient. While some patients may feel mild abdominal pressure or cramping, it is generally well-tolerated.

Please arrive one hour before your appointment time.

Mandatory: You must be accompanied by a friend or family member for support.

The procedure itself usually takes 15 to 30 minutes, though you should plan to be at the clinic for about 2–3 hours.

General guidelines suggest starting at age 45, or earlier if you have a family history of colon issues.

Solid food leaves residue in the colon that can block the camera’s view, making it impossible to see small polyps.

Anything you can see through: water, black tea, lemon water, apple juice, and clear broths.

Yes, but only black coffee. No milk, cream, or dairy substitutes are allowed.

Yes, Jeevan Jal is excellent for maintaining electrolytes during the preparation process.

Red and purple dyes can look like blood or stain the colon wall, leading to inaccurate results.

No. Dairy products are strictly prohibited on the day before and the day of the procedure.

No, avoid "saag" and other high-fiber greens for at least 24 hours before the prep begins.

It is a Polyethylene Glycol (PEG) solution that acts as a powerful laxative to flush out your bowels.

Try drinking it through a straw or chilling the water beforehand. You can also suck on a lemon slice between sips.

Most people feel the urge for a bowel movement within 1 to 2 hours of starting the solution.

Don't panic. For some, it takes longer. Stay active—walking around the house can help move the solution through your system.

Yes, unless your stools are already as clear and yellow as urine. Completing the dose ensures a perfect "prep."

Seeing the green tablet in your stool is usually not a concern. The tablet has a special "enteric coating" designed to dissolve slowly in the intestines. Because the bowel prep (Lactulose and PEG) speeds up your digestion, the outer shell sometimes passes before it can fully dissolve.

As long as you are having frequent bowel movements, the medicine has been absorbed. Do not take an extra dose; simply continue with your 2-liter PEG solution as planned.

Generally, yes, but consult Dr. Shekhar Poudel first. Some diabetes meds (like Metformin) may need to be adjusted.

Stop drinking for 30 minutes, then try again more slowly. If you cannot keep it down, contact NGLC immediately.

Yes. Since we perform the procedure without sedation, you will be fully alert and capable of driving yourself home or returning to work immediately. However, bringing a companion is still recommended for support and to help you remember the doctor's post-procedure advice.

This allows time for registration, vital sign checks, and final consultations with the medical team.

Wear loose, comfortable clothing and leave jewelry or valuables at home.

You will be given a medical gown to wear during the procedure to ensure your privacy and comfort.

Initial findings are often shared immediately. If a biopsy is taken, results usually take 3 to 7 days.

Start with light foods like soups or plain rice. Avoid heavy, oily, or spicy meals for the first few hours.

Yes. Air is used to inflate the colon during the test. Walking and passing gas will relieve this quickly.

Most patients return to work the following day.

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How to Prepare for Your Colonoscopy: Step-by-step Guide by Dr. Shekhar Poudel I National Gastro Liver Center

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