Bowel Preparation Before a Colonoscopy

Bowel preparation before a colonoscopy helps empty the bowel so the doctor can see the bowel lining clearly. Good preparation is important because stool left in the bowel can hide polyps, bleeding or abnormal areas.

This article is for general information only. Always follow the instructions given by your hospital, doctor, nurse or endoscopy unit.

Why Bowel Preparation Is Important

If the bowel is not clean enough, the colonoscopy may be harder to complete or less accurate. In some cases, the test may need to be repeated.

Guy’s and St Thomas’ NHS guidance explains that diet and bowel preparation solution help make sure the bowel is empty, and if guidance is not followed, the procedure may need to be cancelled and rebooked. :contentReference[oaicite:5]{index=5}

Diet Changes

You may be asked to change what you eat before the test. Some people are told to follow a low-fibre diet for a short time, then stop solid food before the procedure.

The exact diet instructions vary, so use the written instructions from your clinic rather than general advice alone.

Taking Bowel Preparation Solution

You may be prescribed laxatives or a bowel preparation drink. This causes frequent watery bowel movements to clear the bowel.

For more information, read our Taking Prescribed Laxatives Before a Bowel Test article.

Drinking Clear Fluids

Clear fluids are often important during preparation because they help prevent dehydration while the bowel is being emptied.

Visit our Drink Clear Fluids Before a Bowel Test article for more details.

Medicines and Safety

Tell the endoscopy unit if you take blood thinners, diabetes medicines, iron tablets or other important medicines. Also tell them if you have kidney disease, heart problems, pregnancy concerns or previous reactions to bowel preparation products.

Your team may adjust instructions to keep you safe.

Final Thoughts

Bowel preparation is one of the most important parts of colonoscopy. Follow the timing carefully, stay near a toilet and contact the clinic if you are unsure or if you become unwell.