Before your test
How to prepare for a colonoscopy: a day-by-day plan
A colonoscopy is only as good as the bowel preparation. When the bowel is clean, even small polyps can be seen and removed; when it is not, the test may have to be repeated. Preparing takes two days of simple changes and one evening and morning of drinking the cleansing solution. This page turns that into a plan with your own dates and times.
In short
Eat low-fibre food for 2 days before, switch to clear liquids from noon the day before, and drink the bowel preparation in two halves: the evening before and again starting about 5 hours before the test. Stop all drinks 2 hours before, and come with someone who can take you home.
Your plan, with dates and times →
Your plan, with dates and times
Enter the date and time of your test. The plan below updates to show exactly when to do each step.
The second half falls very early in the morning. Some hospitals give the whole preparation the evening before for early tests, so check your instruction sheet.
- 7 days beforeStop iron tablets. Ask your doctor about blood thinners, diabetes medicines and insulin.
- 2 days beforeStart the low-fibre diet: no seeds, salads, whole grains or fruit with peel.
- 1 day before, 12 noonLow-fibre breakfast in the morning, then clear liquids only from 12 noon.
- 1 day before, 7 pmFirst half of the bowel preparation. Drink it over 1 to 2 hours, then keep sipping clear liquids.
- 5 hours beforeSecond half of the bowel preparation. Finish it within about an hour.
- 2 hours beforeStop all drinks, including water.
- 30 minutes beforeReach the hospital with an adult who can take you home.
- At the test timeColonoscopy
This is a general plan. If your hospital gives you a different instruction sheet, follow theirs.
What to eat before a colonoscopy
Fibre and seeds stay in the bowel and hide the lining, so the two days before are about plain, soft, low-fibre food.
Eat (2 days before)
- White rice, khichdi made with dhuli moong, suji upma or idli
- White bread, plain dosa, poha without peanuts
- Curd, paneer, eggs, fish or chicken without skin
- Boiled potato without peel, bottle gourd or pumpkin cooked soft
- Banana, papaya without seeds
Avoid (2 days before)
- Seeds: til, flax, chia, tomato and cucumber seeds, guava
- Salads, leafy greens, peas, corn, rajma, chana and dal with skins
- Whole wheat, bajra, oats, multigrain atta and brown rice
- Nuts, dry fruits and fruit with peel
- Iron tablets (from a week before)
Clear liquids (from noon the day before)
- Water, ORS and coconut water
- Clear soup without bits
- Tea or coffee without milk
- Light-coloured juice without pulp, nimbu pani
- No milk, lassi, red or purple drinks
Drinking the preparation
The cleansing solution is the hardest part. These tips make it easier:
- Chill it in the fridge and drink it through a straw
- Drink a glass every 10 to 15 minutes rather than all at once
- Walk around between glasses; it helps the bowel move
- Suck a lemon slice or sip clear juice between glasses
- If you feel sick, pause for 30 minutes, then continue more slowly
- Stay near a toilet; loose motions start within 1 to 3 hours
How do you know the bowel is clean?
By the end of the second half, your stool should be clear, yellow liquid. If it is still brown, call the hospital before you leave.
Medicines to check a week before
Do not stop any medicine on your own. Tell your doctor about these when the test is booked:
Blood thinners
Aspirin, clopidogrel and other blood thinners may need to be paused if polyps are removed. This is decided with the doctor who prescribed them.
Diabetes medicines and insulin
You eat less during the preparation, so the dose usually needs to change for a day or two to avoid low sugar. Check your sugar more often.
Iron tablets
Stop them about a week before. They make the bowel dark and sticky.
BP, heart and thyroid tablets
Usually continued, with a small sip of water on the morning of the test.
Kidney or heart disease, older age
The preparation causes fluid loss. Tell the doctor, as you may need a different solution or extra care.
What to bring
Tick them off the night before.
After the test
- You rest for about an hour. Bloating and passing wind for a few hours are normal.
- Eat a light meal first, then your normal food, unless you are told otherwise after polyp removal.
- Do not drive, work with machines or sign important papers for the rest of the day.
- Biopsy and polyp reports usually take about a week.
Call the hospital or go to an emergency department if you have
- Severe or worsening belly pain, or a hard, swollen belly
- More than a few spoonfuls of blood from the back passage
- Fever, dizziness or fainting
- During the preparation: vomiting that stops you drinking it, or feeling faint
Common questions
Can I drink tea on the day before?
Yes, tea or coffee without milk is a clear liquid. Stop all drinks 2 hours before the test.
What if I vomit the preparation?
Stop for 30 minutes, then drink more slowly. If you cannot keep it down at all, call the hospital, as the test may need to be rescheduled.
What if my stool is not clear by the morning?
Call the hospital before you leave home. A poorly prepared bowel can hide polyps, and the team may give you extra preparation or a new date.
Why the low-fibre diet?
Fibre, seeds and peels stay in the bowel even after the cleansing drink and can hide the lining or block the scope.
Is a colonoscopy painful?
It is usually done under sedation. You may feel some cramping or wind, which settles soon after. The preparation is often the hardest part.
Do I need someone with me?
Yes. After sedation you should not drive or travel alone for the rest of the day.
Read next
References (1)
Clinical guidelines this page follows. They are written for doctors.
- Jacobson BC, Anderson JC, Burke CA, et al. Optimizing Bowel Preparation Quality for Colonoscopy: Consensus Recommendations by the US Multi-Society Task Force on Colorectal Cancer. American Journal of Gastroenterology 2025. doi:10.14309/ajg.0000000000003287