The essentials in 30 seconds: Colonoscopy preparation involves a low-residue diet for 3 days, switching to a liquid diet the day before, and taking a laxative (Pleinvue) in two split doses: one the night before and one on the morning of the procedure. Preparation is correct when stools are completely liquid and clear. A companion is mandatory if you will receive sedation. Always follow your medical team's specific instructions; this guide is for general orientation.
3 days before: the diet
Follow a low-residue diet (also called a low-fibre diet) to reduce intestinal waste before the laxative cleanse.
You can eat
Meat, chicken, fish, rice and pasta with oil and salt, strained broths, eggs. For breakfast: 2 slices of white bread with cooked ham or turkey. Yoghurts and skimmed milk. Coffee, tea and herbal infusions.
You cannot eat
Fruit, vegetables, pulses, potatoes, wholegrain products, nuts, processed meats, any sauces, juices, fizzy drinks or alcohol.
The day before the colonoscopy
Switch to a liquid diet: water, strained broths, herbal infusions, strained juices, gelatine (no dark colouring).
The laxative: Pleinvue (split-dose)
We recommend Pleinvue taken in a split-dose — two parts. This approach is recommended by European endoscopy guidelines for better bowel cleansing and tolerability.
Morning colonoscopy
- 19:00 the night before — 1st dose: Dissolve the sachet in 500 ml of water (3 glasses). Take one glass every 15 minutes. When finished, drink 500 ml of plain water.
- 21:00 the night before — 2nd dose: Dissolve the two sachets in 500 ml of water. Take one glass every 15 minutes. Finish with 500 ml of plain water. That night: liquids only.
- Remember: Complete fasting 8 hours before the procedure (no solids, liquids or medication).
Afternoon colonoscopy
- The night before: Liquids only.
- 08:00 on the day — 1st dose: Dissolve sachet in 500 ml. One glass every 15 minutes, then 500 ml of plain water.
- 10:00 on the day — 2nd dose: Dissolve two sachets in 500 ml. One glass every 15 minutes, finish with 500 ml of water. Must finish before 12:00. Complete fasting from that point.
Practical tip: Drink the preparation cold (better taste). Take breaks between glasses if nauseous. Stay close to a bathroom: the effect starts 1–2 hours after the first dose.
On the day of the colonoscopy
After completing the second dose, complete fasting begins. If your colonoscopy is in the afternoon, you may drink clear liquids up to 4 hours before your appointment.
- Arrive 30 minutes before your appointment
- Come with a companion — mandatory if you will receive sedation
- Bring: insurance card, referral letter, signed informed consent
- Wear comfortable clothing
Medication: what to adjust
| Medication | General instruction |
|---|---|
| Anticoagulants, antiplatelets, Aspirin | Notify the service in advance |
| Diabetes or heart medication | Notify the service in advance |
| Oral iron or fibre supplements | Stop 7 days before |
| Saxenda | Stop 7 days before |
| Ozempic, Mounjaro or Wegovy | Stop 15 days before |
| Pacemaker carrier or latex allergy | Notify the service |
If in doubt about your medication, consult your doctor or call +34 93 219 26 58.
Ozempic, Mounjaro or Wegovy: stop 15 days before. Saxenda: 7 days before. These drugs slow gastric emptying and may affect bowel preparation and sedation safety.
How do I know if preparation has been successful?
Preparation successful
Stools completely liquid and clear (pale yellow or transparent), like lemonade. No visible solid residue.
Preparation needs improvement
Stools still dark, cloudy or with visible solid residue. Come to your appointment anyway — the medical team will assess if the colonoscopy can proceed.
Frequently asked questions about preparation
It depends on your schedule. If the colonoscopy is in the morning, preparation starts the previous evening. Many people prefer to take the day off, but it is not mandatory.
The effect starts 1–2 hours after the first dose and may last 4–6 hours. Stay close to a bathroom.
Yes, it is common. Drink the preparation cold, take breaks between glasses, sip slowly. A lemon sweet between sips can help.
Generally yes, with a small sip of water at least 2 hours before. Consult your doctor if in doubt.
Stools completely liquid and clear, like lemonade. If not fully clear, come anyway — the team will assess if the colonoscopy can go ahead.
Book the colonoscopy first thing in the morning to minimise fasting time. Consult your doctor on medication adjustments.
Morning colonoscopy: complete fasting after the second dose. Afternoon colonoscopy: clear liquids up to 4 hours before.