Colonoscopy Preparation: Diet, Drinks, and What you might notice

Based on NHS, NICE and healthdirect guidance. General information only: always follow the specific instructions from your endoscopy unit.

Take a photo of your wound each day or every few days. The ghost overlay lines up your previous photo so you can see exactly what has changed. The reveal slider lets you drag between before and after. Bring the photos to your next appointment: your GP or surgeon will appreciate the visual record.

All photos stay on your device. Nothing is uploaded. No account needed.

The Colonoscopy Itself

Briefly, so you know what's coming:

• Check-in, gown change, IV cannula placed
• Sedation (light sedation or sometimes general anaesthetic): you'll be drowsy but most people don't remember the procedure
• Procedure takes 20–45 minutes
• You'll need 1–2 hours of recovery, then can go home with someone
• Don't drive, sign documents, or make important decisions for 24 hours
• Some bloating and gas afterwards is normal (air is used to inflate the bowel for inspection)
• Initial results are usually discussed before discharge; biopsy/polyp results take 1–2 weeks

Frequently Asked Questions

Can I take my regular medications before colonoscopy?

Most medications continue as normal up to the day of the procedure. The exceptions: iron tablets (stop 1 week before), blood thinners (often paused, depending on what you take), diabetes medications (often dose-adjusted on prep day and morning of procedure), and GLP-1 agonists like Ozempic, Wegovy, Mounjaro (increasingly being held for several days before due to delayed stomach emptying). Always confirm with your endoscopy unit.

What if I'm constipated normally?

Tell your endoscopy unit when you book. They may prescribe a stronger or earlier-starting prep regimen, or a longer low-fibre diet phase.

Can I have black coffee before the procedure?

Usually yes, until the cut-off time specified by your unit (often 2–4 hours before). Black, no milk or sugar substitute. No cream.

What if my output isn't clear by the morning?

Call your endoscopy unit. They may delay the procedure, give an additional enema on arrival, or postpone if prep is genuinely incomplete. Brown output means the colon isn't fully cleared and polyps may be missed.

Can I do colonoscopy prep at home with diabetes?

Yes, with extra care. Your diabetes team or endoscopy unit will give specific guidance: usually halving or omitting insulin and oral hypoglycaemics on prep day, monitoring blood sugars more frequently, and using sugary clear fluids (apple juice, clear lemonade) rather than diet versions to prevent hypoglycaemia.

What happens if I can't finish the prep?

Get as much down as you can. Contact your endoscopy unit — they may proceed if output is clear, or rebook with a different prep next time. Some people find one product unbearable but tolerate another well.