Colonoscopy preparation instructions
Content date: 13 November 2026
Stool left in the colon can hide polyps and other abnormal areas. If the bowel is not clean enough, the doctor may miss a finding or be unable to complete the examination. You may need to repeat the preparation and colonoscopy.
Your next step
Follow the food, dose and fluid instructions for your prescribed preparation. If you cannot finish it, keep vomiting, or still have dark or solid stool near your appointment, call the unit before the procedure.
Get urgent help: Severe pain with swelling or inability to pass gas, heavy bleeding or clots, fainting, fever or breathlessness after the procedure; or severe dehydration during preparation.
Calculate your preparation and fasting timetable
Enter the date and actual procedure start, not arrival time.
Select the product and plan prescribed by your endoscopy unit.
Use the standard plan only after your team confirms suitability, especially with pregnancy, fluid restriction, kidney or heart disease, a severe IBD flare or delayed stomach emptying. If obstruction is suspected or severe pain is worsening, do not start the laxative; seek assessment.
Do not enter personal information; inputs stay on this page and are not sent to the clinic. Keep a copy of your timetable.
What to expect on procedure day
Written guidance: preparation
Reads the displayed text using an available voice on your device.
Read the instructions
Confirm the type of endoscopy, the date, the procedure start time and the arrival time with your unit. Arrival and procedure start may be different.
Follow your prescribed preparation sheet. For colonoscopy, confirm the product, fluid amounts and dose times. Use the calculator only when its plan matches your unit’s prescription.
Check your last food and drink times and your medicine plan with the team, especially blood thinners and diabetes or weight-management medicines. Do not stop or change a medicine yourself.
If you cannot finish preparation, keep vomiting or fall behind the timetable, contact the unit. Do not double doses, rush fluids to catch up or drink after the cutoff.
If sedation is planned, arrange an escort home. Bring your medicine list and reports, and follow your written instructions.
Start with your prescribed product and confirmed procedure time. Follow one timetable combining food, preparation medicine and drinks; tick each step after completing it.
Regular medicines before endoscopy
Review your complete medicine and supplement list with the endoscopy unit at least a week before the appointment, and earlier if a longer interruption may be needed. Get a written plan for every medicine that needs adjustment.
- Medicines that may continue: Examples include amlodipine or bisoprolol for blood pressure, levothyroxine for thyroid disease and levetiracetam for epilepsy, according to the team’s plan. Bring asthma inhalers. Fasting does not mean stopping every medicine.
- Taking an approved dose: Use a small sip of water at the agreed time. Any dose after the drinking cutoff needs explicit instructions from the unit. Do not independently stop seizure medicines, long-term steroids or transplant medicines.
- Medicines needing a separate plan: Insulin and diabetes medicines, including SGLT2 and GLP-1 medicines, diuretics and some heart and blood-pressure medicines. The team sets what to continue or hold and when to restart. Do not stop all insulin yourself.
- Blood thinners: Examples include warfarin, apixaban and clopidogrel. Any interruption or adjustment needs an agreed plan from the prescribing doctor and gastroenterologist. Low-dose aspirin usually continues for most endoscopic procedures.
- During bowel cleansing: Oral medicine absorption may decrease; ask the pharmacist about spacing from your preparation. Iron, antidiarrheal medicines or fiber supplements may need a temporary pause. Colonoscopy alone does not require stopping a PPI; the plan differs if H. pylori testing is also planned.
Full guide: my medicines before endoscopy, interruption and restarting
Preparation reference — open only what you need
Picoprep preparation
Tell the team about kidney or heart disease, a fluid restriction, diabetes, pregnancy, severe constipation, previous poor preparation or possible bowel obstruction. You may need a different product or schedule. Get individual instructions for blood thinners, diabetes and weight-management medicines; do not change them yourself.
The last meal
For afternoon appointments from 2 pm, the clinic’s standard Picoprep plan permits a small low-fiber dinner the previous evening. Finish by the time shown in your timetable, no later than 9 pm and before the first sachet. Examples: white toast with an egg, or a small portion of plain white rice. Avoid fatty meals, whole grains, seeds, salad, dates and nuts. After that: clear fluids only, with no solid food on the procedure day.
For earlier appointments, finish a light low-fiber lunch by noon the day before, then clear fluids only. A different product or higher risk of poor preparation may require stricter food instructions; your written plan takes priority.
Both sachets have fixed times
First sachet: take it at the exact date and time shown. The time changes with your appointment; for late appointments it can be on the procedure day. Second sachet: take it exactly 6 hours before the procedure; do not postpone it to the end of a time window.
Mix each sachet with the water volume specified on your pack and prescription; do not confuse mixing water with the extra fluids. After each sachet in this clinic plan, drink one 250 mL glass of clear fluid every 20 minutes, eight glasses in total (2 liters over 2 hours 40 minutes). The calculator lists the times. Bisacodyl (Dulcolax) in the clinic-prescribed plan: take 10 mg by mouth once only (two 5 mg tablets) with the first Picoprep sachet. Do not repeat the dose with the second sachet or add other laxatives yourself.
Stop all drinking 3 hours before the procedure, including water, clear fluids and preparation. If you start late, vomit or cannot finish, contact the endoscopy unit. Do not rush the remaining fluid or drink past the cutoff. Tell the team what you took and when.
Previous evening: finish a light dinner by 9 pm; take the first sachet with bisacodyl 10 mg once at 10 pm and finish its 2 liters of clear fluids by 12:40 am. Procedure day: take the second sachet at 10 am and finish its 2 liters by 12:40 pm. Stop all drinking at 1 pm. For any other appointment time, use the calculator.
Moviprep: prescribed split dose
For each dose, dissolve sachets A and B together in water to a final volume of one liter. Drink over one to two hours, followed by 500 mL of permitted clear liquids. Take the first dose the evening before and the second on the day of the procedure. Confirm the timetable and fasting cutoff with your unit.
Clear fluids and the expected result
Use a variety of permitted clear fluids: water, tea or coffee without milk, clear pulp-free apple juice or strained broth without pieces or visible fat. Do not rely on water alone. No milk, laban, smoothies, pulpy juice or red/purple drinks. This applies to colonoscopy preparation even when gastroscopy is done at the same session.
Is coffee allowed despite its dark color?
Yes. For colonoscopy preparation, filtered black coffee is an allowed clear fluid if it has no milk, creamer, cream, plant milk, grounds or sediment. Clear does not mean colorless here. Do not use Turkish coffee or Arabic coffee containing grounds, ground cardamom or sediment. Water, plain tea or clear apple juice are alternatives. Vary your fluids rather than relying on coffee alone, and observe the drinking cutoff.
This applies to colonoscopy preparation, including a combined gastroscopy and colonoscopy. For gastroscopy alone, this clinic allows water only during the food fast; coffee and tea are not allowed during that period.
Stool should become watery, light yellow or nearly clear without solid pieces. Complete the prescribed preparation even if this happens early. If stool stays dark or contains pieces, or you cannot finish, contact the unit promptly. Do not depend on a delayed message reply.
Sudden severe abdominal pain, marked swelling, fainting, severe weakness, persistent vomiting or markedly reduced urine need prompt assessment. Do not add laxatives to overcome these symptoms.
Product and mixing-water volume: ................................
First sachet + bisacodyl 10 mg once, date/time: ................ | Second sachet without repeat bisacodyl, date/time: ................
Extra fluids after each: ................ | Stop all fluids: ................
Last meal: ................ | Medicine adjustments: ................
After sedation, arrange an adult escort and do not drive, operate machinery or make important decisions for at least 24 hours, or longer if instructed.
Why this timetable?
Bisacodyl 10 mg once is a prescribed addition in this clinic plan, not a universal ASGE requirement. ASGE/USMSTF 2025 supports split dosing, starting the second portion 4–6 hours before and finishing at least 2 hours before the procedure. This clinic selects a fixed 6-hour start and a 3-hour drinking cutoff. The dinner allowance is the clinic’s individualized low-fiber plan for suitable afternoon patients, not a universal ASGE instruction. Do not use it if your unit prescribed stricter preparation.
Food and drink examples — full reference
What can I eat before colonoscopy?
These examples separate the low-fiber food stage from the clear-fluid stage. Most adults at low risk of poor preparation only need diet changes on the day before; severe constipation or a previous poor preparation may require an earlier start prescribed by the team.
| Stage | Suitable choices | What should I avoid? |
|---|---|---|
| Low-fiber food stage, before your timetable’s last meal | Boiled eggs; white toast or plain white Arabic bread without seeds; plain white rice or pasta; skinless chicken or fish, not fried; peeled potatoes. Plain yogurt or low-fat labneh without pieces can fit if allowed by your plan. | Whole-grain bread or grains; whole-wheat jareesh or harees; oats; dates and dried fruit; nuts and seeds; ful, lentils and chickpeas; salads and fruit or vegetables with skins or seeds. |
| After your stated last meal until the drinking cutoff | Clear fluids only: water; plain tea or filtered black coffee without milk, creamer or sediment; clear apple juice without pulp; strained chicken or meat broth without pieces or visible fat. | All solid food, even low-fiber food. Milk, laban, yogurt, smoothies and pulpy juices are not clear fluids. Avoid lentil or cream soup and red or purple fluids. |
| From the drinking cutoff until the procedure | No food or drink. Take medicine with a sip of water only if the team explicitly permits it. | Do not extend drinking because you arrived early or the procedure is delayed; check with the team first. |
For an afternoon appointment on the clinic’s standard Picoprep plan, a small low-fiber dinner is permitted the previous evening, finished at the calculator’s time and no later than 9 pm. For an earlier appointment, stop solids after the prescribed lunch. After the last meal, clear fluids only. Do not use this dinner allowance with a different or stricter preparation plan.
Drink the extra fluids specified for your product gradually. Vary the permitted clear fluids rather than relying only on water. People with diabetes need a glucose and medicine plan; those with heart or kidney disease or a fluid restriction need amounts set by the team.
When to get help
Severe pain with swelling or inability to pass gas, heavy bleeding or clots, fainting, fever or breathlessness after the procedure; or severe dehydration during preparation.
If your medicine or fasting instructions are unclear, call the endoscopy unit before starting preparation.
Guides for your care journey
Read the related guides together:
Related guides
Sources
ASGE: Diabetes and weight-loss medicines before endoscopy, 2025
Multisociety guidance: Individual GLP-1 plans
USMSTF: Bowel preparation, 2025
ASGE / USMSTF bowel preparation 2025
ASGE: Eating after colonoscopy
PICOPREP: trial of product-specific tailored dosing
Saudi FDA: PICOPREP product registration